Shifting surgical strategies in ischemic mitral regurgitation

SNOWMASS, COLO. – In a major reversal of longstanding opinion, thought leaders in cardiothoracic surgery now increasingly favor mitral valve replacement over repair in patients with severe ischemic mitral regurgitation.

The overwhelming preference among both surgeons and cardiologists has been for mitral valve repair, but recent randomized trial evidence shows that mitral valve replacement provides a more durable correction with no increase in adverse events. That’s persuaded many surgical leaders to move towards replacement until improved repair strategies can be developed, Dr. Vinod H. Thourani said at the Annual Cardiovascular Conference at Snowmass.

“When I do a replacement in a patient, the cardiologist will call me and ask why. He’ll say, ‘I was hoping you were going to do a repair.’ Now we have to completely change our mentality about this,” said Dr. Thourani, professor of surgery and codirector of the Structural Heart and Valve Center at Emory University in Atlanta.

That need for a mind-shift goes for cardiothoracic surgeons as well as cardiologists, he added, pointing to an analysis of the Society of Thoracic Surgeons adult cardiac surgery database for 2008-2012 showing roughly a 65%-35% preference for repair over replacement.

The evidence favoring mitral valve replacement is so new it didn’t make it into the deliberations that generated the freshly minted 2014 ACC/AHA guidelines on valvular heart disease management (J. Am. Coll. Cardiol. 2014;63:e57-185), which state that “there is no conclusive evidence for superiority of repair or replacement” in severe ischemic mitral regurgitation (MR). That statement is no longer true, in Dr. Thourani’s view.

He highlighted a multicenter randomized trial conducted by the Cardiothoracic Surgical Trials Network (CSTN) in which 251 patients with severe ischemic mitral regurgitation were randomized to repair or replacement. The primary endpoint – change in left ventricular end-systolic volume index indicative of reversal of ventricular remodeling – improved similarly in both groups. Nor did the two treatment groups differ significantly in 30-day and 12-month mortality or rates of stroke, heart failure, bleeding, infection, and other major adverse events. The eye opener was that 32.6% of patients in the repair group had moderate or severe mitral regurgitation at 12 months, compared with just 2.3% in the replacement group (N. Engl. J. Med. 2014;370:23-32).

“This study was done at a group of high-functioning academic centers where surgeons are supposed to know how to do repair and do replacement, yet one-third of our patients have come back with moderate to severe MR after repair. This has opened up a lot of discussion among surgeons as to what we should be doing,” noted Dr. Thourani, who participated in the trial.

One-year mortality was 14.2% in the repair group and a statistically similar 17.6% in the valve-replacement group, but Dr. Thourani anticipates a steeper mortality rise ahead for the repair group. “It’ll be interesting to see where these patients living with recurrent MR will be at the 2- and 5-year marks,” he said.

In a subsequent analysis, the CSTN investigators examined whether baseline clinical and echocardiographic characteristics in patients randomized to repair could identify a subgroup at high risk for recurrent moderate-to-severe mitral regurgitation or death within 2 years post surgery. They identified a predictive model that shows promise, with a favorable area under the receiver operating characteristic curve of 0.82.

The model is based on 10 factors: age; gender; race; body mass index; New York Heart Association class; effective regurgitant orifice area; basal aneurysm/dyskinesia; and history of coronary artery bypass grafting, percutaneous coronary intervention, or ventricular arrhythmias (J. Thorac. Cardiovasc. Surg. 2014 Nov 6. pii: S0022-5223(14)01772-3).

Of these 10 variables, the standout predictor was basal aneurysm/dyskinesia. “If you repair those patients, they have a really high likelihood of having worse outcomes,” according to Dr. Thourani.

This analysis of the CSTN repair subgroup shed new light on the MR-recurrence phenomenon. Roughly 30% of patients had recurrent moderate or severe MR at 1 month after surgery. By 24 months, that figure had climbed to 46%. There was little progression from moderate to severe MR over time, but MR recurrence was a dynamic phenomenon: Roughly 10% of affected patients experienced reversal of recurrent MR at various time points.

The randomized CSTN findings showing better results with mitral valve replacement were supported by the results of the Italian Study on the Treatment of Ischemic Mitral Regurgitation (ISTIMIR). This was a multicenter observational study of 1,006 patients with ischemic MR, 30% of whom underwent valve replacement while 70% had a repair. In a propensity-matched multivariate logistic regression analysis, mitral valve repair was associated with a 2.84-fold increased risk of reoperation within 8 years (J. Thorac. Cardiovasc. Surg. 2013;145:128-39).

Although mitral annuloplasty remains the current standard of care for repair of severe ischemic MR in 2015, “we’re realizing this isn’t necessarily the right thing to do” because of that high recurrent MR rate, Dr. Thourani said. There is a growing understanding that a subannular component is required to achieve a truly successful repair. A variety of promising subannular approaches are being developed. He is particularly enthusiastic about his own group’s work involving creation of a papillary muscle sling to achieve papillary approximation – the results have been encouraging in roughly 40 treated sheep and pigs. Human studies are coming.

Ischemic MR develops secondary to an acute MI, which imposes volume overload on the left ventricle, with increasing wall stress, left ventricular remodeling and heart failure, papillary muscle disarray, annular dilation, and MR. The incidence of heart failure within 5 years is threefold higher if an MI occurs with ischemic MR than without it, the surgeon observed.

The CSTN studies were sponsored by the National Institutes of Health and the Canadian Institutes of Health. Dr. Thourani reported serving as a consultant to Edwards Lifesciences and St. Jude Medical and receiving research grants from Abbott, Boston Scientific, Medtronic, and Sorin.

bjancin@frontlinemedcom.com

SNOWMASS, COLO. – In a major reversal of longstanding opinion, thought leaders in cardiothoracic surgery now increasingly favor mitral valve replacement over repair in patients with severe ischemic mitral regurgitation.

The overwhelming preference among both surgeons and cardiologists has been for mitral valve repair, but recent randomized trial evidence shows that mitral valve replacement provides a more durable correction with no increase in adverse events. That’s persuaded many surgical leaders to move towards replacement until improved repair strategies can be developed, Dr. Vinod H. Thourani said at the Annual Cardiovascular Conference at Snowmass.

“When I do a replacement in a patient, the cardiologist will call me and ask why. He’ll say, ‘I was hoping you were going to do a repair.’ Now we have to completely change our mentality about this,” said Dr. Thourani, professor of surgery and codirector of the Structural Heart and Valve Center at Emory University in Atlanta.

That need for a mind-shift goes for cardiothoracic surgeons as well as cardiologists, he added, pointing to an analysis of the Society of Thoracic Surgeons adult cardiac surgery database for 2008-2012 showing roughly a 65%-35% preference for repair over replacement.

The evidence favoring mitral valve replacement is so new it didn’t make it into the deliberations that generated the freshly minted 2014 ACC/AHA guidelines on valvular heart disease management (J. Am. Coll. Cardiol. 2014;63:e57-185), which state that “there is no conclusive evidence for superiority of repair or replacement” in severe ischemic mitral regurgitation (MR). That statement is no longer true, in Dr. Thourani’s view.

He highlighted a multicenter randomized trial conducted by the Cardiothoracic Surgical Trials Network (CSTN) in which 251 patients with severe ischemic mitral regurgitation were randomized to repair or replacement. The primary endpoint – change in left ventricular end-systolic volume index indicative of reversal of ventricular remodeling – improved similarly in both groups. Nor did the two treatment groups differ significantly in 30-day and 12-month mortality or rates of stroke, heart failure, bleeding, infection, and other major adverse events. The eye opener was that 32.6% of patients in the repair group had moderate or severe mitral regurgitation at 12 months, compared with just 2.3% in the replacement group (N. Engl. J. Med. 2014;370:23-32).

“This study was done at a group of high-functioning academic centers where surgeons are supposed to know how to do repair and do replacement, yet one-third of our patients have come back with moderate to severe MR after repair. This has opened up a lot of discussion among surgeons as to what we should be doing,” noted Dr. Thourani, who participated in the trial.

One-year mortality was 14.2% in the repair group and a statistically similar 17.6% in the valve-replacement group, but Dr. Thourani anticipates a steeper mortality rise ahead for the repair group. “It’ll be interesting to see where these patients living with recurrent MR will be at the 2- and 5-year marks,” he said.

In a subsequent analysis, the CSTN investigators examined whether baseline clinical and echocardiographic characteristics in patients randomized to repair could identify a subgroup at high risk for recurrent moderate-to-severe mitral regurgitation or death within 2 years post surgery. They identified a predictive model that shows promise, with a favorable area under the receiver operating characteristic curve of 0.82.

The model is based on 10 factors: age; gender; race; body mass index; New York Heart Association class; effective regurgitant orifice area; basal aneurysm/dyskinesia; and history of coronary artery bypass grafting, percutaneous coronary intervention, or ventricular arrhythmias (J. Thorac. Cardiovasc. Surg. 2014 Nov 6. pii: S0022-5223(14)01772-3).

Of these 10 variables, the standout predictor was basal aneurysm/dyskinesia. “If you repair those patients, they have a really high likelihood of having worse outcomes,” according to Dr. Thourani.

This analysis of the CSTN repair subgroup shed new light on the MR-recurrence phenomenon. Roughly 30% of patients had recurrent moderate or severe MR at 1 month after surgery. By 24 months, that figure had climbed to 46%. There was little progression from moderate to severe MR over time, but MR recurrence was a dynamic phenomenon: Roughly 10% of affected patients experienced reversal of recurrent MR at various time points.

The randomized CSTN findings showing better results with mitral valve replacement were supported by the results of the Italian Study on the Treatment of Ischemic Mitral Regurgitation (ISTIMIR). This was a multicenter observational study of 1,006 patients with ischemic MR, 30% of whom underwent valve replacement while 70% had a repair. In a propensity-matched multivariate logistic regression analysis, mitral valve repair was associated with a 2.84-fold increased risk of reoperation within 8 years (J. Thorac. Cardiovasc. Surg. 2013;145:128-39).

Although mitral annuloplasty remains the current standard of care for repair of severe ischemic MR in 2015, “we’re realizing this isn’t necessarily the right thing to do” because of that high recurrent MR rate, Dr. Thourani said. There is a growing understanding that a subannular component is required to achieve a truly successful repair. A variety of promising subannular approaches are being developed. He is particularly enthusiastic about his own group’s work involving creation of a papillary muscle sling to achieve papillary approximation – the results have been encouraging in roughly 40 treated sheep and pigs. Human studies are coming.

Ischemic MR develops secondary to an acute MI, which imposes volume overload on the left ventricle, with increasing wall stress, left ventricular remodeling and heart failure, papillary muscle disarray, annular dilation, and MR. The incidence of heart failure within 5 years is threefold higher if an MI occurs with ischemic MR than without it, the surgeon observed.

The CSTN studies were sponsored by the National Institutes of Health and the Canadian Institutes of Health. Dr. Thourani reported serving as a consultant to Edwards Lifesciences and St. Jude Medical and receiving research grants from Abbott, Boston Scientific, Medtronic, and Sorin.

bjancin@frontlinemedcom.com

SNOWMASS, COLO. – In a major reversal of longstanding opinion, thought leaders in cardiothoracic surgery now increasingly favor mitral valve replacement over repair in patients with severe ischemic mitral regurgitation.

The overwhelming preference among both surgeons and cardiologists has been for mitral valve repair, but recent randomized trial evidence shows that mitral valve replacement provides a more durable correction with no increase in adverse events. That’s persuaded many surgical leaders to move towards replacement until improved repair strategies can be developed, Dr. Vinod H. Thourani said at the Annual Cardiovascular Conference at Snowmass.

“When I do a replacement in a patient, the cardiologist will call me and ask why. He’ll say, ‘I was hoping you were going to do a repair.’ Now we have to completely change our mentality about this,” said Dr. Thourani, professor of surgery and codirector of the Structural Heart and Valve Center at Emory University in Atlanta.

That need for a mind-shift goes for cardiothoracic surgeons as well as cardiologists, he added, pointing to an analysis of the Society of Thoracic Surgeons adult cardiac surgery database for 2008-2012 showing roughly a 65%-35% preference for repair over replacement.

The evidence favoring mitral valve replacement is so new it didn’t make it into the deliberations that generated the freshly minted 2014 ACC/AHA guidelines on valvular heart disease management (J. Am. Coll. Cardiol. 2014;63:e57-185), which state that “there is no conclusive evidence for superiority of repair or replacement” in severe ischemic mitral regurgitation (MR). That statement is no longer true, in Dr. Thourani’s view.

He highlighted a multicenter randomized trial conducted by the Cardiothoracic Surgical Trials Network (CSTN) in which 251 patients with severe ischemic mitral regurgitation were randomized to repair or replacement. The primary endpoint – change in left ventricular end-systolic volume index indicative of reversal of ventricular remodeling – improved similarly in both groups. Nor did the two treatment groups differ significantly in 30-day and 12-month mortality or rates of stroke, heart failure, bleeding, infection, and other major adverse events. The eye opener was that 32.6% of patients in the repair group had moderate or severe mitral regurgitation at 12 months, compared with just 2.3% in the replacement group (N. Engl. J. Med. 2014;370:23-32).

“This study was done at a group of high-functioning academic centers where surgeons are supposed to know how to do repair and do replacement, yet one-third of our patients have come back with moderate to severe MR after repair. This has opened up a lot of discussion among surgeons as to what we should be doing,” noted Dr. Thourani, who participated in the trial.

One-year mortality was 14.2% in the repair group and a statistically similar 17.6% in the valve-replacement group, but Dr. Thourani anticipates a steeper mortality rise ahead for the repair group. “It’ll be interesting to see where these patients living with recurrent MR will be at the 2- and 5-year marks,” he said.

In a subsequent analysis, the CSTN investigators examined whether baseline clinical and echocardiographic characteristics in patients randomized to repair could identify a subgroup at high risk for recurrent moderate-to-severe mitral regurgitation or death within 2 years post surgery. They identified a predictive model that shows promise, with a favorable area under the receiver operating characteristic curve of 0.82.

The model is based on 10 factors: age; gender; race; body mass index; New York Heart Association class; effective regurgitant orifice area; basal aneurysm/dyskinesia; and history of coronary artery bypass grafting, percutaneous coronary intervention, or ventricular arrhythmias (J. Thorac. Cardiovasc. Surg. 2014 Nov 6. pii: S0022-5223(14)01772-3).

Of these 10 variables, the standout predictor was basal aneurysm/dyskinesia. “If you repair those patients, they have a really high likelihood of having worse outcomes,” according to Dr. Thourani.

This analysis of the CSTN repair subgroup shed new light on the MR-recurrence phenomenon. Roughly 30% of patients had recurrent moderate or severe MR at 1 month after surgery. By 24 months, that figure had climbed to 46%. There was little progression from moderate to severe MR over time, but MR recurrence was a dynamic phenomenon: Roughly 10% of affected patients experienced reversal of recurrent MR at various time points.

The randomized CSTN findings showing better results with mitral valve replacement were supported by the results of the Italian Study on the Treatment of Ischemic Mitral Regurgitation (ISTIMIR). This was a multicenter observational study of 1,006 patients with ischemic MR, 30% of whom underwent valve replacement while 70% had a repair. In a propensity-matched multivariate logistic regression analysis, mitral valve repair was associated with a 2.84-fold increased risk of reoperation within 8 years (J. Thorac. Cardiovasc. Surg. 2013;145:128-39).

Although mitral annuloplasty remains the current standard of care for repair of severe ischemic MR in 2015, “we’re realizing this isn’t necessarily the right thing to do” because of that high recurrent MR rate, Dr. Thourani said. There is a growing understanding that a subannular component is required to achieve a truly successful repair. A variety of promising subannular approaches are being developed. He is particularly enthusiastic about his own group’s work involving creation of a papillary muscle sling to achieve papillary approximation – the results have been encouraging in roughly 40 treated sheep and pigs. Human studies are coming.

Ischemic MR develops secondary to an acute MI, which imposes volume overload on the left ventricle, with increasing wall stress, left ventricular remodeling and heart failure, papillary muscle disarray, annular dilation, and MR. The incidence of heart failure within 5 years is threefold higher if an MI occurs with ischemic MR than without it, the surgeon observed.

The CSTN studies were sponsored by the National Institutes of Health and the Canadian Institutes of Health. Dr. Thourani reported serving as a consultant to Edwards Lifesciences and St. Jude Medical and receiving research grants from Abbott, Boston Scientific, Medtronic, and Sorin.

bjancin@frontlinemedcom.com