Faisal Aziz, MD

 

Open repair should be offered to all patients with rAAA

With the advent of endovascular repair of abdominal aortic aneurysms (EVAR), the treatment of elective AAAs was revolutionized. Since ruptured abdominal aortic aneurysms (rAAAs) carry a higher morbidity and mortality than elective AAA repair the use of EVAR has been advocated for these patients.¹ Dr. Aziz contends that EVAR should be utilized in all patients presenting with a rAAA. It is my contention that endovascular repair cannot replace open aneurysm repair in all situations. The best treatment option should be offered taking patient and institutional considerations into account. Forcing a given procedure and trying to “make it work” is not best for the patient.

In a systematic literature review of patients presenting with rAAAs, selection bias regarding treatment choice (EVAR vs. open repair) was found consistently.² In an effort to show that EVAR is superior to open repair for rAAA, Hinchliffe et al. published a randomized trial that showed no difference in 30-day mortality (53%) in each treatment group.³ The AJAX trial randomized 116 patients and did not show benefit for EVAR with respect to 30-day morbidity or mortality.⁴ The ECAR trial randomized 107 patients and also failed to show a difference in mortality between EVAR and open techniques for rAAA.⁵

In many of these studies, hemodynamic instability has led to patient bias: more stable patients were chosen for EVAR, leaving the critical patients to undergo open repair. It has been established that patients with free rupture and instability fare with worse outcomes, regardless of the treatment option, than those who are stable.⁶ Anatomy also creates a bias as patients with unsuitable anatomy are more likely to be repaired open, while those with favorable anatomy are repaired with EVAR.

Determining suitability for EVAR includes assessing diameter of the neck of the aneurysm, angulation, size of iliac arteries, presence of atherosclerotic occlusive disease, presence of accessory renal arteries, and presence of concurrent aneurysms of the iliac arteries.^7,8 In the IMPROVE trial, patients were randomized depending on anatomic suitability for EVAR.⁹ Anatomy was determined by imaging in those patients stable enough to undergo preoperative computed tomography angiogram (CTA). Therefore, given anatomic differences, patients presenting with rAAA were not randomized without significant treatment bias.

A true pararenal or paravisceral rupture certainly elevates the complexity of the case. Open repair can deal with this difficult challenge by adapting additional established techniques to the situation. Although some authors have advocated EVAR for rAAA using snorkels and chimneys, these techniques may not be appropriate in the treatment of rAAA in most institutions.¹⁰ These procedures take longer, require considerable experience and resources and are therefore not appropriate in unstable patients. No randomized control trial exists at this time to address superiority of EVAR to open repair in patients with complex anatomy.

Patients presenting with rAAA that have had prior endovascular intervention also pose complex anatomic and technical challenges.¹¹ These patients can present with hemodynamic instability and rupture but now are complicated by having device failure. Salvage using endovascular means may not be possible. The risk of re-intervention with endovascular repair for rAAA is much higher than with open repair.¹²

Emergency vascular surgery is best approached with protocols and systems in place no matter what approach is chosen.¹³ Skilled staff in the emergency department and in the operating room must be available without delay especially for rAAA, as time is of the essence. Skilled surgeons, skilled operating room staff, knowledgeable anesthesia staff are necessary to quickly move a patient from the emergency department to the operating room for definitive treatment. Other ancillary services, such as blood banks and laboratories are necessary to assist in the care for the patient intraoperatively. In endovascular surgery, trained technologists, fluoroscopy, a full armamentarium of interventional equipment (wires, balloons, stents, etc.), and a full stock of stent grafts and associated ancillary equipment are mandatory. Many hospitals may not have the variety of stent grafts available for emergency use. Regionalization of care has been suggested to improve outcomes in the treatment of rAAAs.¹⁴ In a study by Warner et al., mortality was decreased by 20% at the tertiary center compared to the smaller community hospitals in both EVAR and open repairs for rAAA. Zettervall et al. published data that showed that significant regional variation exists in perioperative outcomes and length of stay, and mortality in repair for rAAA approached with open or endovascular means.¹⁵ Low volume centers have worse outcomes, and teaching hospitals may have better outcomes treating AAA.16

EVAR is also reported to be associated with a 27-36% higher cost of care than open surgery for rAAA.¹⁷ Many institutions may not have the means to provide the resources needed to support such a program.

There is no question that EVAR has greatly impacted the treatment of aortic aneurysms. However, not every aneurysm is appropriate for endovascular repair at this time. For the many reasons cited, we cannot permit open repair to become an extinct skill. Vascular training programs must include open repair of rAAA just as it should for other vascular conditions.

I would agree with Dr. Aziz that we do not yet have a prospective, randomized study and Level 1 evidence to support either view and given the complexity and urgency associated with these patients, such a study may not be forthcoming. Till then, patients with a RAAA should have ‘all of the above’ approach including open surgery depending on the institutional experience and resources and urgency of the situation.

References

1. J Vasc Surg 2016; 2:297-305

2. J Vasc Surg 2009; 49:1077-1080.

3. Eur J Vasc Endovasc Surg 2006; 32:506-513

4. Ann Surg 2013. Aug 258 (2) 248-56

5. J Vasc Surg 2010; 51:267-70

6. Ann Vasc Surg 2017; 38:59-63

7. J Vasc Surg 2009: 50:243-50

8. J Endovasc Ther 2016; 23: 919-927

9. BJM 2014; 101:216-224

10. Radiographics 2015; 35:593-615.

11. Ann Vasc Surg 2013; 27:844-50

12. J Vasc Surg 2017; 65:52-57

13. Semin Vasc Surg 2016; 29:35-40

14. J Vasc Surg 2014; 59:1512-7

15. Ann Surg 2017; 264:538-43

16. J Vasc Surg 2016; 22 pii W0741-5214 (16) 31247-2

17. J Vasc Surg 2008; 47:1165-70

Dr. Ozsvatrh is a professor of surgery at Albany Medical College, Albany, N.Y., and a vascular attending, at Albany Medical Center Hospital, Albany, and chief, department of surgery, Samaritan Hospital, Troy, N.Y.

EVAR should be offered to all patients with rAAA

Since the inception of EVAR two decades ago, it has largely replaced open abdominal aortic aneurysm repair as the operation of choice for elective treatment of abdominal aortic aneurysms. Shorter duration of operation, avoiding general anesthesia and aortic cross clamping, ability to obtain balloon control of aorta, fast recovery time and reduced hospital length of hospital stay are among the most commonly cited reasons for this change in paradigm for treatment of abdominal aortic aneurysms. Since vascular surgeons have adopted the widespread use of EVAR, the total number of aneurysm related deaths has significantly reduced.¹ While EVAR has become the most commonly used operation to treat AAAs electively, it’s utility to treat ruptured AAAs has been questioned. Recent analysis of nationwide trends for the operations for the diagnosis of ruptured AAA show that almost half of the patients with ruptured AAA are still treated with open surgical repair.²

Opponents of REVAR (EVAR for rAAA) cite comparable outcomes of open surgery and REVAR in randomized controlled trials, requirement of a specific REVAR protocol, increased cost and lack of resources and more importantly, lack of level I evidence to support it’s use in all cases of rAAA.

AAA rupture is a catastrophe and most people with ruptured AAA die immediately due to massive blood loss. Patients with ruptured AAA who can be brought to a hospital are in a sate of severe hemodynamic compromise. In such individuals, human body’s innate responses are able to maintain a blood pressure by achieving severe vasoconstriction of peripheral vasculature to compensate for severe systemic hypotension. REVAR is associated with minimal trauma to body and avoids the need for exploratory laparotomy and aortic cross clamping, and hence, minimizes the fluid shifts and hemodynamic compromise in patients with severe hypovolemic shock.

It is no surprise that REVAR is associated with significantly lower perioperative mortality (24%) as compared to open repair of ruptured AAA (44%).³ Mortality after open repair of ruptured AAA can vary anywhere from 30-70%.^4,5 Improved mortality rates after REVAR are not only limited to stable patients, but also extend to those patients with ruptured AAA who are considered hemodynamically unstable at the time of initial presentation.⁶

The survival advantage among REVAR patients is not only evident in short term (30-days), but it also extends up to 5 years after the operation.³ Patients undergoing REVAR are less likely to require intra-operative blood transfusions, as compared to patients who undergo open repair of rAAA.⁷ Development of acute renal failure after surgical treatment of rAAAs is associated with significant mortality and REVAR has been associated with significantly lower incidence of acute renal failure as compared to open repair of ruptured AAA.²

Due to inherent issues of patient instability, emergent presentation and inequality among hospital resources and patient volumes, it is difficult to design a flawless, randomized controlled trial to compare REVAR with open surgical repair. The results from published randomized controlled trials on this topic should be interpreted with caution. The Nottingham trial from the United Kingdom⁸ showed similar mortality (53%) between REVAR and open surgical operation, however, out of the 203 patients enrolled in the trial, 70% were not randomized and REVAR was offered to only 15 patients. Likewise, the AJAX Trial from Netherlands⁹ showed that there was no significant difference in mortality between the two treatment groups (42% with REVAR and 47% with open repair), however almost 80% of enrolled patients were not randomized and there was a disagreement between the interpreters about CTA diagnosis of rAAA. In addition, the conversion rates from REVAR to open repair were unexpectedly high (14%), pointing to the surgeons’ inexperience.

Similarly, the IMPROVE trial from United Kingdom¹⁰ suffered from poor rates of randomization (50% of enrolled patients) and poor methodology (obtaining CTA after randomization, and making requirement of CTA optional for patients allocated to open surgery group). The trial showed equivalent mortality rates between the two surgical groups (35% with REVAR and 37% with open repair).

Due to flawed methodology and poor rates of randomization, results of these trials do not provide us with level I evidence, which is required to make any scientific recommendations about the treatment of choice for the treatment of rAAAs. Hence, the large body of evidence, obtained from retrospective studies should be used while comparing the outcomes of operations for ruptured AAAs. So far, all retrospective analyses, comparing REVAR with open repair in national registries, such as National Inpatient Sample (NIS) database^11,12 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database⁷ and Medicare database¹³ have clearly shown that the outcomes of REVAR are better than open surgical repair of ruptured AAA. Likewise, multi-center observational studies^14,15 have demonstrated superiority of REVAR over open surgical repair.

To summarize, REVAR is a safe procedure, can be performed under local anesthetic, has shorter operative time and is associated with improved outcomes as compared to open surgery. REVAR should be the treatment of choice for all patients who meet the anatomic criteria for endovascular repair. With increasing experience of vascular surgeons with the endovascular technology, it is foreseeable that REVAR will soon become the treatment of choice for ruptured abdominal aortic aneurysms.

References

1. J Vasc Surg 2009;49:543-50; discussion 50-1.

2. Ann Vasc Surg 2016;35:147-55.

3. J Vasc Surg 2013;57:368-75.

4. J Vasc Surg 2001;34:41-6.

5. J Vasc Surg 1991;13:240-5; discussion 5-7.

6. J Vasc Surg 2014;60:1439-45.

7. J Vasc Surg 2010;51:305-9 e1.

8. Eur J Vasc Endovasc Surg 2006;32:506-13; discussion 14-5.

9. Ann Surg 2013;258:248-56.

10. BMJ 2014;348:f7661.

11. J Vasc Surg 2009;49:817-26.

12. J Vasc Surg 2008;47:1165-70; discussion 70-1.

13. J Vasc Surg 2014;59:575-82.

14. Ann Surg 2012;256:688-95; discussion 95-6.

15. Ann Surg 2009;250:818-24.

Dr. Aziz is in the division of vascular surgery, Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, Penn.

 

Open repair should be offered to all patients with rAAA

With the advent of endovascular repair of abdominal aortic aneurysms (EVAR), the treatment of elective AAAs was revolutionized. Since ruptured abdominal aortic aneurysms (rAAAs) carry a higher morbidity and mortality than elective AAA repair the use of EVAR has been advocated for these patients.¹ Dr. Aziz contends that EVAR should be utilized in all patients presenting with a rAAA. It is my contention that endovascular repair cannot replace open aneurysm repair in all situations. The best treatment option should be offered taking patient and institutional considerations into account. Forcing a given procedure and trying to “make it work” is not best for the patient.

In a systematic literature review of patients presenting with rAAAs, selection bias regarding treatment choice (EVAR vs. open repair) was found consistently.² In an effort to show that EVAR is superior to open repair for rAAA, Hinchliffe et al. published a randomized trial that showed no difference in 30-day mortality (53%) in each treatment group.³ The AJAX trial randomized 116 patients and did not show benefit for EVAR with respect to 30-day morbidity or mortality.⁴ The ECAR trial randomized 107 patients and also failed to show a difference in mortality between EVAR and open techniques for rAAA.⁵

In many of these studies, hemodynamic instability has led to patient bias: more stable patients were chosen for EVAR, leaving the critical patients to undergo open repair. It has been established that patients with free rupture and instability fare with worse outcomes, regardless of the treatment option, than those who are stable.⁶ Anatomy also creates a bias as patients with unsuitable anatomy are more likely to be repaired open, while those with favorable anatomy are repaired with EVAR.

Determining suitability for EVAR includes assessing diameter of the neck of the aneurysm, angulation, size of iliac arteries, presence of atherosclerotic occlusive disease, presence of accessory renal arteries, and presence of concurrent aneurysms of the iliac arteries.^7,8 In the IMPROVE trial, patients were randomized depending on anatomic suitability for EVAR.⁹ Anatomy was determined by imaging in those patients stable enough to undergo preoperative computed tomography angiogram (CTA). Therefore, given anatomic differences, patients presenting with rAAA were not randomized without significant treatment bias.

A true pararenal or paravisceral rupture certainly elevates the complexity of the case. Open repair can deal with this difficult challenge by adapting additional established techniques to the situation. Although some authors have advocated EVAR for rAAA using snorkels and chimneys, these techniques may not be appropriate in the treatment of rAAA in most institutions.¹⁰ These procedures take longer, require considerable experience and resources and are therefore not appropriate in unstable patients. No randomized control trial exists at this time to address superiority of EVAR to open repair in patients with complex anatomy.

Patients presenting with rAAA that have had prior endovascular intervention also pose complex anatomic and technical challenges.¹¹ These patients can present with hemodynamic instability and rupture but now are complicated by having device failure. Salvage using endovascular means may not be possible. The risk of re-intervention with endovascular repair for rAAA is much higher than with open repair.¹²

Emergency vascular surgery is best approached with protocols and systems in place no matter what approach is chosen.¹³ Skilled staff in the emergency department and in the operating room must be available without delay especially for rAAA, as time is of the essence. Skilled surgeons, skilled operating room staff, knowledgeable anesthesia staff are necessary to quickly move a patient from the emergency department to the operating room for definitive treatment. Other ancillary services, such as blood banks and laboratories are necessary to assist in the care for the patient intraoperatively. In endovascular surgery, trained technologists, fluoroscopy, a full armamentarium of interventional equipment (wires, balloons, stents, etc.), and a full stock of stent grafts and associated ancillary equipment are mandatory. Many hospitals may not have the variety of stent grafts available for emergency use. Regionalization of care has been suggested to improve outcomes in the treatment of rAAAs.¹⁴ In a study by Warner et al., mortality was decreased by 20% at the tertiary center compared to the smaller community hospitals in both EVAR and open repairs for rAAA. Zettervall et al. published data that showed that significant regional variation exists in perioperative outcomes and length of stay, and mortality in repair for rAAA approached with open or endovascular means.¹⁵ Low volume centers have worse outcomes, and teaching hospitals may have better outcomes treating AAA.16

EVAR is also reported to be associated with a 27-36% higher cost of care than open surgery for rAAA.¹⁷ Many institutions may not have the means to provide the resources needed to support such a program.

There is no question that EVAR has greatly impacted the treatment of aortic aneurysms. However, not every aneurysm is appropriate for endovascular repair at this time. For the many reasons cited, we cannot permit open repair to become an extinct skill. Vascular training programs must include open repair of rAAA just as it should for other vascular conditions.

I would agree with Dr. Aziz that we do not yet have a prospective, randomized study and Level 1 evidence to support either view and given the complexity and urgency associated with these patients, such a study may not be forthcoming. Till then, patients with a RAAA should have ‘all of the above’ approach including open surgery depending on the institutional experience and resources and urgency of the situation.

References

1. J Vasc Surg 2016; 2:297-305

2. J Vasc Surg 2009; 49:1077-1080.

3. Eur J Vasc Endovasc Surg 2006; 32:506-513

4. Ann Surg 2013. Aug 258 (2) 248-56

5. J Vasc Surg 2010; 51:267-70

6. Ann Vasc Surg 2017; 38:59-63

7. J Vasc Surg 2009: 50:243-50

8. J Endovasc Ther 2016; 23: 919-927

9. BJM 2014; 101:216-224

10. Radiographics 2015; 35:593-615.

11. Ann Vasc Surg 2013; 27:844-50

12. J Vasc Surg 2017; 65:52-57

13. Semin Vasc Surg 2016; 29:35-40

14. J Vasc Surg 2014; 59:1512-7

15. Ann Surg 2017; 264:538-43

16. J Vasc Surg 2016; 22 pii W0741-5214 (16) 31247-2

17. J Vasc Surg 2008; 47:1165-70

Dr. Ozsvatrh is a professor of surgery at Albany Medical College, Albany, N.Y., and a vascular attending, at Albany Medical Center Hospital, Albany, and chief, department of surgery, Samaritan Hospital, Troy, N.Y.

EVAR should be offered to all patients with rAAA

Since the inception of EVAR two decades ago, it has largely replaced open abdominal aortic aneurysm repair as the operation of choice for elective treatment of abdominal aortic aneurysms. Shorter duration of operation, avoiding general anesthesia and aortic cross clamping, ability to obtain balloon control of aorta, fast recovery time and reduced hospital length of hospital stay are among the most commonly cited reasons for this change in paradigm for treatment of abdominal aortic aneurysms. Since vascular surgeons have adopted the widespread use of EVAR, the total number of aneurysm related deaths has significantly reduced.¹ While EVAR has become the most commonly used operation to treat AAAs electively, it’s utility to treat ruptured AAAs has been questioned. Recent analysis of nationwide trends for the operations for the diagnosis of ruptured AAA show that almost half of the patients with ruptured AAA are still treated with open surgical repair.²

Opponents of REVAR (EVAR for rAAA) cite comparable outcomes of open surgery and REVAR in randomized controlled trials, requirement of a specific REVAR protocol, increased cost and lack of resources and more importantly, lack of level I evidence to support it’s use in all cases of rAAA.

AAA rupture is a catastrophe and most people with ruptured AAA die immediately due to massive blood loss. Patients with ruptured AAA who can be brought to a hospital are in a sate of severe hemodynamic compromise. In such individuals, human body’s innate responses are able to maintain a blood pressure by achieving severe vasoconstriction of peripheral vasculature to compensate for severe systemic hypotension. REVAR is associated with minimal trauma to body and avoids the need for exploratory laparotomy and aortic cross clamping, and hence, minimizes the fluid shifts and hemodynamic compromise in patients with severe hypovolemic shock.

It is no surprise that REVAR is associated with significantly lower perioperative mortality (24%) as compared to open repair of ruptured AAA (44%).³ Mortality after open repair of ruptured AAA can vary anywhere from 30-70%.^4,5 Improved mortality rates after REVAR are not only limited to stable patients, but also extend to those patients with ruptured AAA who are considered hemodynamically unstable at the time of initial presentation.⁶

The survival advantage among REVAR patients is not only evident in short term (30-days), but it also extends up to 5 years after the operation.³ Patients undergoing REVAR are less likely to require intra-operative blood transfusions, as compared to patients who undergo open repair of rAAA.⁷ Development of acute renal failure after surgical treatment of rAAAs is associated with significant mortality and REVAR has been associated with significantly lower incidence of acute renal failure as compared to open repair of ruptured AAA.²

Due to inherent issues of patient instability, emergent presentation and inequality among hospital resources and patient volumes, it is difficult to design a flawless, randomized controlled trial to compare REVAR with open surgical repair. The results from published randomized controlled trials on this topic should be interpreted with caution. The Nottingham trial from the United Kingdom⁸ showed similar mortality (53%) between REVAR and open surgical operation, however, out of the 203 patients enrolled in the trial, 70% were not randomized and REVAR was offered to only 15 patients. Likewise, the AJAX Trial from Netherlands⁹ showed that there was no significant difference in mortality between the two treatment groups (42% with REVAR and 47% with open repair), however almost 80% of enrolled patients were not randomized and there was a disagreement between the interpreters about CTA diagnosis of rAAA. In addition, the conversion rates from REVAR to open repair were unexpectedly high (14%), pointing to the surgeons’ inexperience.

Similarly, the IMPROVE trial from United Kingdom¹⁰ suffered from poor rates of randomization (50% of enrolled patients) and poor methodology (obtaining CTA after randomization, and making requirement of CTA optional for patients allocated to open surgery group). The trial showed equivalent mortality rates between the two surgical groups (35% with REVAR and 37% with open repair).

Due to flawed methodology and poor rates of randomization, results of these trials do not provide us with level I evidence, which is required to make any scientific recommendations about the treatment of choice for the treatment of rAAAs. Hence, the large body of evidence, obtained from retrospective studies should be used while comparing the outcomes of operations for ruptured AAAs. So far, all retrospective analyses, comparing REVAR with open repair in national registries, such as National Inpatient Sample (NIS) database^11,12 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database⁷ and Medicare database¹³ have clearly shown that the outcomes of REVAR are better than open surgical repair of ruptured AAA. Likewise, multi-center observational studies^14,15 have demonstrated superiority of REVAR over open surgical repair.

To summarize, REVAR is a safe procedure, can be performed under local anesthetic, has shorter operative time and is associated with improved outcomes as compared to open surgery. REVAR should be the treatment of choice for all patients who meet the anatomic criteria for endovascular repair. With increasing experience of vascular surgeons with the endovascular technology, it is foreseeable that REVAR will soon become the treatment of choice for ruptured abdominal aortic aneurysms.

References

1. J Vasc Surg 2009;49:543-50; discussion 50-1.

2. Ann Vasc Surg 2016;35:147-55.

3. J Vasc Surg 2013;57:368-75.

4. J Vasc Surg 2001;34:41-6.

5. J Vasc Surg 1991;13:240-5; discussion 5-7.

6. J Vasc Surg 2014;60:1439-45.

7. J Vasc Surg 2010;51:305-9 e1.

8. Eur J Vasc Endovasc Surg 2006;32:506-13; discussion 14-5.

9. Ann Surg 2013;258:248-56.

10. BMJ 2014;348:f7661.

11. J Vasc Surg 2009;49:817-26.

12. J Vasc Surg 2008;47:1165-70; discussion 70-1.

13. J Vasc Surg 2014;59:575-82.

14. Ann Surg 2012;256:688-95; discussion 95-6.

15. Ann Surg 2009;250:818-24.

Dr. Aziz is in the division of vascular surgery, Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, Penn.

 

Open repair should be offered to all patients with rAAA

With the advent of endovascular repair of abdominal aortic aneurysms (EVAR), the treatment of elective AAAs was revolutionized. Since ruptured abdominal aortic aneurysms (rAAAs) carry a higher morbidity and mortality than elective AAA repair the use of EVAR has been advocated for these patients.¹ Dr. Aziz contends that EVAR should be utilized in all patients presenting with a rAAA. It is my contention that endovascular repair cannot replace open aneurysm repair in all situations. The best treatment option should be offered taking patient and institutional considerations into account. Forcing a given procedure and trying to “make it work” is not best for the patient.

In a systematic literature review of patients presenting with rAAAs, selection bias regarding treatment choice (EVAR vs. open repair) was found consistently.² In an effort to show that EVAR is superior to open repair for rAAA, Hinchliffe et al. published a randomized trial that showed no difference in 30-day mortality (53%) in each treatment group.³ The AJAX trial randomized 116 patients and did not show benefit for EVAR with respect to 30-day morbidity or mortality.⁴ The ECAR trial randomized 107 patients and also failed to show a difference in mortality between EVAR and open techniques for rAAA.⁵

In many of these studies, hemodynamic instability has led to patient bias: more stable patients were chosen for EVAR, leaving the critical patients to undergo open repair. It has been established that patients with free rupture and instability fare with worse outcomes, regardless of the treatment option, than those who are stable.⁶ Anatomy also creates a bias as patients with unsuitable anatomy are more likely to be repaired open, while those with favorable anatomy are repaired with EVAR.

Determining suitability for EVAR includes assessing diameter of the neck of the aneurysm, angulation, size of iliac arteries, presence of atherosclerotic occlusive disease, presence of accessory renal arteries, and presence of concurrent aneurysms of the iliac arteries.^7,8 In the IMPROVE trial, patients were randomized depending on anatomic suitability for EVAR.⁹ Anatomy was determined by imaging in those patients stable enough to undergo preoperative computed tomography angiogram (CTA). Therefore, given anatomic differences, patients presenting with rAAA were not randomized without significant treatment bias.

A true pararenal or paravisceral rupture certainly elevates the complexity of the case. Open repair can deal with this difficult challenge by adapting additional established techniques to the situation. Although some authors have advocated EVAR for rAAA using snorkels and chimneys, these techniques may not be appropriate in the treatment of rAAA in most institutions.¹⁰ These procedures take longer, require considerable experience and resources and are therefore not appropriate in unstable patients. No randomized control trial exists at this time to address superiority of EVAR to open repair in patients with complex anatomy.

Patients presenting with rAAA that have had prior endovascular intervention also pose complex anatomic and technical challenges.¹¹ These patients can present with hemodynamic instability and rupture but now are complicated by having device failure. Salvage using endovascular means may not be possible. The risk of re-intervention with endovascular repair for rAAA is much higher than with open repair.¹²

Emergency vascular surgery is best approached with protocols and systems in place no matter what approach is chosen.¹³ Skilled staff in the emergency department and in the operating room must be available without delay especially for rAAA, as time is of the essence. Skilled surgeons, skilled operating room staff, knowledgeable anesthesia staff are necessary to quickly move a patient from the emergency department to the operating room for definitive treatment. Other ancillary services, such as blood banks and laboratories are necessary to assist in the care for the patient intraoperatively. In endovascular surgery, trained technologists, fluoroscopy, a full armamentarium of interventional equipment (wires, balloons, stents, etc.), and a full stock of stent grafts and associated ancillary equipment are mandatory. Many hospitals may not have the variety of stent grafts available for emergency use. Regionalization of care has been suggested to improve outcomes in the treatment of rAAAs.¹⁴ In a study by Warner et al., mortality was decreased by 20% at the tertiary center compared to the smaller community hospitals in both EVAR and open repairs for rAAA. Zettervall et al. published data that showed that significant regional variation exists in perioperative outcomes and length of stay, and mortality in repair for rAAA approached with open or endovascular means.¹⁵ Low volume centers have worse outcomes, and teaching hospitals may have better outcomes treating AAA.16

EVAR is also reported to be associated with a 27-36% higher cost of care than open surgery for rAAA.¹⁷ Many institutions may not have the means to provide the resources needed to support such a program.

There is no question that EVAR has greatly impacted the treatment of aortic aneurysms. However, not every aneurysm is appropriate for endovascular repair at this time. For the many reasons cited, we cannot permit open repair to become an extinct skill. Vascular training programs must include open repair of rAAA just as it should for other vascular conditions.

I would agree with Dr. Aziz that we do not yet have a prospective, randomized study and Level 1 evidence to support either view and given the complexity and urgency associated with these patients, such a study may not be forthcoming. Till then, patients with a RAAA should have ‘all of the above’ approach including open surgery depending on the institutional experience and resources and urgency of the situation.

References

1. J Vasc Surg 2016; 2:297-305

2. J Vasc Surg 2009; 49:1077-1080.

3. Eur J Vasc Endovasc Surg 2006; 32:506-513

4. Ann Surg 2013. Aug 258 (2) 248-56

5. J Vasc Surg 2010; 51:267-70

6. Ann Vasc Surg 2017; 38:59-63

7. J Vasc Surg 2009: 50:243-50

8. J Endovasc Ther 2016; 23: 919-927

9. BJM 2014; 101:216-224

10. Radiographics 2015; 35:593-615.

11. Ann Vasc Surg 2013; 27:844-50

12. J Vasc Surg 2017; 65:52-57

13. Semin Vasc Surg 2016; 29:35-40

14. J Vasc Surg 2014; 59:1512-7

15. Ann Surg 2017; 264:538-43

16. J Vasc Surg 2016; 22 pii W0741-5214 (16) 31247-2

17. J Vasc Surg 2008; 47:1165-70

Dr. Ozsvatrh is a professor of surgery at Albany Medical College, Albany, N.Y., and a vascular attending, at Albany Medical Center Hospital, Albany, and chief, department of surgery, Samaritan Hospital, Troy, N.Y.

EVAR should be offered to all patients with rAAA

Since the inception of EVAR two decades ago, it has largely replaced open abdominal aortic aneurysm repair as the operation of choice for elective treatment of abdominal aortic aneurysms. Shorter duration of operation, avoiding general anesthesia and aortic cross clamping, ability to obtain balloon control of aorta, fast recovery time and reduced hospital length of hospital stay are among the most commonly cited reasons for this change in paradigm for treatment of abdominal aortic aneurysms. Since vascular surgeons have adopted the widespread use of EVAR, the total number of aneurysm related deaths has significantly reduced.¹ While EVAR has become the most commonly used operation to treat AAAs electively, it’s utility to treat ruptured AAAs has been questioned. Recent analysis of nationwide trends for the operations for the diagnosis of ruptured AAA show that almost half of the patients with ruptured AAA are still treated with open surgical repair.²

Opponents of REVAR (EVAR for rAAA) cite comparable outcomes of open surgery and REVAR in randomized controlled trials, requirement of a specific REVAR protocol, increased cost and lack of resources and more importantly, lack of level I evidence to support it’s use in all cases of rAAA.

AAA rupture is a catastrophe and most people with ruptured AAA die immediately due to massive blood loss. Patients with ruptured AAA who can be brought to a hospital are in a sate of severe hemodynamic compromise. In such individuals, human body’s innate responses are able to maintain a blood pressure by achieving severe vasoconstriction of peripheral vasculature to compensate for severe systemic hypotension. REVAR is associated with minimal trauma to body and avoids the need for exploratory laparotomy and aortic cross clamping, and hence, minimizes the fluid shifts and hemodynamic compromise in patients with severe hypovolemic shock.

It is no surprise that REVAR is associated with significantly lower perioperative mortality (24%) as compared to open repair of ruptured AAA (44%).³ Mortality after open repair of ruptured AAA can vary anywhere from 30-70%.^4,5 Improved mortality rates after REVAR are not only limited to stable patients, but also extend to those patients with ruptured AAA who are considered hemodynamically unstable at the time of initial presentation.⁶

The survival advantage among REVAR patients is not only evident in short term (30-days), but it also extends up to 5 years after the operation.³ Patients undergoing REVAR are less likely to require intra-operative blood transfusions, as compared to patients who undergo open repair of rAAA.⁷ Development of acute renal failure after surgical treatment of rAAAs is associated with significant mortality and REVAR has been associated with significantly lower incidence of acute renal failure as compared to open repair of ruptured AAA.²

Due to inherent issues of patient instability, emergent presentation and inequality among hospital resources and patient volumes, it is difficult to design a flawless, randomized controlled trial to compare REVAR with open surgical repair. The results from published randomized controlled trials on this topic should be interpreted with caution. The Nottingham trial from the United Kingdom⁸ showed similar mortality (53%) between REVAR and open surgical operation, however, out of the 203 patients enrolled in the trial, 70% were not randomized and REVAR was offered to only 15 patients. Likewise, the AJAX Trial from Netherlands⁹ showed that there was no significant difference in mortality between the two treatment groups (42% with REVAR and 47% with open repair), however almost 80% of enrolled patients were not randomized and there was a disagreement between the interpreters about CTA diagnosis of rAAA. In addition, the conversion rates from REVAR to open repair were unexpectedly high (14%), pointing to the surgeons’ inexperience.

Similarly, the IMPROVE trial from United Kingdom¹⁰ suffered from poor rates of randomization (50% of enrolled patients) and poor methodology (obtaining CTA after randomization, and making requirement of CTA optional for patients allocated to open surgery group). The trial showed equivalent mortality rates between the two surgical groups (35% with REVAR and 37% with open repair).

Due to flawed methodology and poor rates of randomization, results of these trials do not provide us with level I evidence, which is required to make any scientific recommendations about the treatment of choice for the treatment of rAAAs. Hence, the large body of evidence, obtained from retrospective studies should be used while comparing the outcomes of operations for ruptured AAAs. So far, all retrospective analyses, comparing REVAR with open repair in national registries, such as National Inpatient Sample (NIS) database^11,12 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database⁷ and Medicare database¹³ have clearly shown that the outcomes of REVAR are better than open surgical repair of ruptured AAA. Likewise, multi-center observational studies^14,15 have demonstrated superiority of REVAR over open surgical repair.

To summarize, REVAR is a safe procedure, can be performed under local anesthetic, has shorter operative time and is associated with improved outcomes as compared to open surgery. REVAR should be the treatment of choice for all patients who meet the anatomic criteria for endovascular repair. With increasing experience of vascular surgeons with the endovascular technology, it is foreseeable that REVAR will soon become the treatment of choice for ruptured abdominal aortic aneurysms.

References

1. J Vasc Surg 2009;49:543-50; discussion 50-1.

2. Ann Vasc Surg 2016;35:147-55.

3. J Vasc Surg 2013;57:368-75.

4. J Vasc Surg 2001;34:41-6.

5. J Vasc Surg 1991;13:240-5; discussion 5-7.

6. J Vasc Surg 2014;60:1439-45.

7. J Vasc Surg 2010;51:305-9 e1.

8. Eur J Vasc Endovasc Surg 2006;32:506-13; discussion 14-5.

9. Ann Surg 2013;258:248-56.

10. BMJ 2014;348:f7661.

11. J Vasc Surg 2009;49:817-26.

12. J Vasc Surg 2008;47:1165-70; discussion 70-1.

13. J Vasc Surg 2014;59:575-82.

14. Ann Surg 2012;256:688-95; discussion 95-6.

15. Ann Surg 2009;250:818-24.

Dr. Aziz is in the division of vascular surgery, Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, Penn.