Intermediate-term outcome of mitral reconstruction in cardiomyopathy

Nontransplant cardiac surgery for end-stage cardiomyopathy

OBJECTIVE

To treat end-stage cardiomyopathy, we evaluated endoventricular circular patch plasty, partial left ventriculectomy, and valvular reconstruction alone in our 2-year experience.

METHODS

Among 86 patients with heart failure evaluated between December 1996 and February 1999, 33 patients with ischemic cardiomyopathy (25 men and 8 women; mean age 61 +/- 7.8 years; New York Heart Association class 3.5 +/- 0.5) were treated with endoventricular circular patch plasty combined with coronary bypass grafting (84%) and mitral reconstruction (36%). The other 53 patients with nonischemic cardiomyopathy (45 men and 8 women; mean age 48 +/- 14.3 years, New York Heart Association class 3.7 +/- 0.5), were treated by left ventricular reduction by partial left ventriculectomy (n = 37) or patch plasty (n = 3) and valve reconstruction alone (n = 13). The first 24 patients (group I) underwent ventriculectomy with or without valve reconstruction; the more recent 29 patients (group II) underwent left ventricular reduction (n = 16) or valve reconstruction alone (n = 13) on the basis of the intraoperative echocardiographic evaluation to observe changes of wall motion and thickness during cardiopulmonary bypass.

RESULTS

Ischemic Group: Hospital mortality in elective (n = 26) and emergency (n = 7) operations was 4% and 43%, and 3 patients died in the late postoperative period. Mean New York Heart Association class and ejection fraction improved from 3.5 +/- 0.5 to 1.5 +/- 0.7 and from 23% +/- 7.7% to 36% +/- 8.6%, respectively. Left ventricular end-diastolic and end-systolic volume indexes decreased from 162 +/- 46 mL/m(2) to 110 +/- 39 mL/m(2) and from 130 +/- 47 mL/m(2) to 70 +/- 32 mL/m(2), respectively. Nonischemic Group: In 40 patients with left ventricular reduction, hospital mortality in elective (n = 33) and emergency (n = 7) operations was 6% and 86%, and 5 patients died in the late postoperative period. Mean New York Heart Association class and ejection fraction improved from 3.7 +/- 0.5 to 1.7 +/- 0.6 and from 18% +/- 6.4% to 31% +/- 5.9%. Left ventricular end-diastolic and end-systolic volume indexes decreased from 203 +/- 45 mL/m(2) to 110 +/- 37 mL/m(2) and from 164 +/- 40 mL/m(2) to 79 +/- 33 mL/m(2), respectively. In 13 patients undergoing valve reconstruction alone (12 mitral with or without tricuspid and 1 tricuspid plus left ventricular assist device), hospital mortality in elective (n = 9) and emergency (n = 4) operations was 0% and 50% with no late deaths. Mean New York Heart Association class and ejection fraction improved from 3.6 +/- 0.5 to 2.0 +/- 0.5 and from 22% +/- 6.0% to 30% +/- 14.5%, respectively. Mean left ventricular end-diastolic and end-systolic volume indexes decreased from 170 +/- 34 mL/m(2) to 150 +/- 50 mL/m(2) and from 140 +/- 38 mL/m(2) to 104 +/- 40 mL/m(2), respectively. Overall mortality decreased from 50% in group I to 10% in group II. The survival estimates at 2 years were 77% (confidence limits 57%-88%) in the ischemic group and 63% (confidence limits 47%-75%) in the nonischemic group (no significant difference). The analysis of our data showed that the factors influencing the surgical results for dilated cardiomyopathy were presence of severe mitral regurgitation, preoperative New York Heart Association functional class IV with emergency operation, and operative procedures with randomly performed partial left ventriculectomy without an intraoperative echo test.

CONCLUSION

Endoventricular circular patch plasty, partial left ventriculectomy, and solo valve reconstruction can be performed with an acceptably low risk as elective operations. The selection of operative procedures in idiopathic dilated cardiomyopathy and avoidance of emergency surgery improved operative mortality and morbidity. Among patients who survived at least 1 year, there were no late deaths up to 30 months' follow-up.

Surgical therapies for heart failure

Heart transplantation remains the best hope for patients with end-stage heart failure unresponsive to conventional therapy, but the number of transplant candidates continues to exceed the number of available donor hearts. Despite major advances in the medical management of heart failure, researchers continue to explore alternative surgical therapies designed to augment cardiac function. Many of these surgical therapies are still in the experimental or clinical trial phases. Surgical approaches include coronary revascularization, mitral valve repair or replacement, cardiomyoplasty, left ventricular volume reduction surgery, and bridging to recovery with the use of ventricular assist devices. Although cardiac surgeons have gained considerable experience in the treatment of patients with heart failure, many improvements and innovations lie ahead.

Does the additive risk of mitral valve repair in patients with ischemic cardiomyopathy prohibit surgical intervention?

OBJECTIVE

To assess the surgical risk of additional mitral valve repairs in patients with ischemic cardiomyopathy.

SUMMARY BACKGROUND DATA

Severe mitral regurgitation in patients with ischemic cardiomyopathy increases the death rate and symptomatic status. The 1-year survival rate for medical therapy in this subset of patients is less than 20%. Transplantation is usually not feasible because of donor shortage and death while on the waiting list.

METHODS

To assess additive risk, a retrospective chart review from 1993 to 1998 was performed comparing patients with ischemic cardiomyopathy (ejection fraction [EF] <25%) and severe mitral regurgitation undergoing mitral valve repair and coronary artery bypass graft operations with patients with an EF of <25% undergoing coronary artery bypass graft alone. These groups were also compared with 140 patients receiving heart transplants since 1993 (group 3).

RESULTS

The overall hospital death rate for group 1 was 6.3%. The one death occurred 2 weeks after surgery secondary to sepsis. This was not significantly different from the death rate of 4.1% in group 2. In group 1, there were two deaths at 1 year (87% survival rate), one related to heart failure. One patient was New York Heart Association (NYHA) class IV at 1 year; the remainder of patients were NYHA class I-II. These results were not significantly different than the 8% death rate noted with transplantation. There was no change in EF and minimal residual mitral regurgitation in group 1 based on postoperative transesophageal echocardiography, whereas group 2 had an average 11.7% improvement in EF.

CONCLUSIONS

Previously, severe mitral regurgitation in the setting of ischemic cardiomyopathy has been associated with poor survival. In these authors' experience, repairing the mitral valve along with coronary artery bypass grafting does not increase the surgical risk, yields improvement in symptomatic status, and compares favorably to coronary artery bypass grafting alone and cardiac transplantation. However, the lack of change in EF in these patients probably represents an overestimation of the EF before surgery secondary to severe mitral regurgitation.

Ring annuloplasty prevents delayed leaflet coaptation and mitral regurgitation during acute left ventricular ischemia

OBJECTIVE

Incomplete mitral leaflet coaptation during acute left ventricular ischemia is associated with end-diastolic mitral annular dilatation and ischemic mitral regurgitation. Annular rings were implanted in sheep to investigate whether annular reduction alone is sufficient to prevent mitral regurgitation during acute posterolateral left ventricular ischemia.

METHODS

Radiopaque markers were inserted around the mitral anulus, on papillary muscle tips, and on the central meridian of both mitral leaflets in three groups of sheep: control (n = 5), Physio ring (n = 5) (Baxter Cardiovascular Div, Santa Ana, Calif), and Duran ring (n = 6) (Medtronic Heart Valve Div, Minneapolis, Minn). After 8 +/- 1 days, animals were studied with biplane videofluoroscopy before and during left ventricular ischemia. Annular area was calculated from 3-dimensional marker coordinates and coaptation defined as minimal distance between leaflet edge markers.

RESULTS

Before ischemia, leaflet coaptation occurred just after end-diastole in all groups (control 17 +/- 41, Duran 33 +/- 30, Physio 33 +/- 24 ms, mean +/- SD, P >.2 by analysis of variance). During ischemia, regurgitation was detected in all control animals, and leaflet coaptation was delayed to 88 +/- 8 ms after end-diastole (P =.02 vs preischemia). This was associated with increased end-diastolic annular area (8.0 +/- 0.9 vs 6.7 +/- 0.6 cm(2), P =.004) and septal-lateral annular diameter (2.9 +/- 0.1 vs 2.5 +/- 0.1 cm, P =.02). Mitral regurgitation did not develop in Duran or Physio sheep, time to coaptation was unchanged (Duran 25 +/- 25 ms, Physio 30 +/- 48 ms [both P >.2 vs preischemia]), and annular area remained fixed.

CONCLUSION

Mitral annular area reduction and fixation with an annuloplasty ring eliminated delayed leaflet coaptation and prevented mitral regurgitation during acute left ventricular ischemia after ring implantation.

Mitral valve surgery in patients with severe left ventricular dysfunction

OBJECTIVES

The objectives of this study were to determine (1) survival, (2) functional status and freedom from readmission for heart failure and (3) change in postoperative left ventricular (LV) dimensions and function following mitral valve repair or replacement in patients with severe LV dysfunction and mitral regurgitation.

PATIENTS AND METHODS

Between 1990 and 1998, 44 patients with mitral regurgitation and a LV ejection fraction <35% (mean+/-SD, 28+/-6%) underwent isolated mitral repair (n=35) or replacement (n=9). The etiology of regurgitation was valvular in 18 (40%) patients, ischemic in 13 (30%) patients and dilated idiopathic cardiomyopathy in 13 (30%) patients. Every patient had been hospitalized one to six times for symptoms of heart failure (mean+/-SD, 2.3+/-1.5). All patients were receiving maximal drug therapy with 15 (34%) in New York Heart Association (NYHA) class III and 12 (27%) in class IV. Seven (16%) patients were initially referred for consideration of transplantation. The mean+/-SD duration of follow-up was 40+/-21 months.

RESULTS

One (2.3%) patient died 9 days postoperatively of acute bronchopneumonia. The mean+/-SD duration of ICU and hospital stay was 41+/-34 h and 9+/-3 days, respectively. The 1-, 2- and 5-year survival rates were 89, 86 and 67%, respectively. Heart failure and sudden death accounted for 62% of the late deaths. The NYHA class improved for survivors from 2.8+/-0.8 preoperatively to 1. 2+/-0.5 at follow-up (P<0.0001). Freedom from readmission for heart failure was 88, 82 and 72% at 1, 2 and 5 years, respectively. No patient has been listed for transplantation.

CONCLUSIONS

Mitral valve surgery offers symptomatic improvement and survival benefit in patients with severe LV dysfunction and mitral regurgitation. More liberal use of this surgery for cardiomyopathy patients is warranted.

Partial left ventriculectomy, ventriculoplasty or valvular surgery for idiopathic dilated cardiomyopathy - the role of intra-operative echocardiography

BACKGROUND

The partial left ventriculectomy (PLV) is known to work in some patients with dilated cardiomyopathy (DCM), although this procedure does not work well in all patients and the operative mortality is higher than the other cardiac surgeries. In addition to PLV, left ventriculoplasty to exclude antero-septal wall or valvular surgery without left ventricle (LV) surgery can be also effective in patients with DCM. To improve the surgical results for dilated cardiomyopathy, we introduced echo-guided volume reduction test and evaluated the surgical procedures and the results on the surgery for DCM.

METHODS

Between December 1996 and July 1999, 56 patients with DCM (50 with idiopathic DCM, six with dilated hypertrophic cardiomyopathy) were surgically treated. Under the standard cardiopulmonary bypass, left ventricular motion was determined with color kinesis of echocardiogram and the lesion of akinetic wall was removed or excluded.

RESULTS

After the initial PLV in 18 patients (initial group), operative procedures were selected in 21 with PLV, five with LV plasty, or 12 with valve surgery without LV surgery according to the findings of the LV wall motion by intraoperative echogram (select group). There were six hospital deaths and late follow-up deaths within 1 year in initial group, however, the mortality decreased significantly after the selection of the operative procedures; three hospital deaths and two late deaths in the select-group (P<0.05). Significant decrease of left ventricular diameter, the LV ejection fraction and endosystolic volume index were demonstrated after the LV surgery. The survival rate improved significantly after the selection of the operative procedures; 14 months survival rates was 50.0% in initial group and 73.1% in select group (P<0.05).

CONCLUSION

Operative mortality decreased and late follow-up results improved after the selection of operative procedures according to the intraoperative volume reduction test.

Surgical approaches to dilated cardiomyopathy

Heart failure is one of the leading causes of hospitalization in the United States today. Congestive heart failure is a chronic progressive disease with the common central element being the remodeling of the cardiac chamber associated with ventricular dilation. Secondary mitral regurgitation is a complication of end-stage cardiomyopathy and is associated with a poor prognosis. Historically, these patients were not considered operative candidates due to the high morbidity and mortality in this patient population. Heart transplantation is now considered the standard of treatment for select patients with end-stage heart disease, however, it is only applicable to a small number of patients. In an effort to address this problem, newer and alternative surgical approaches are evolving, including mitral valve annuloplasty, the Batista myoplasty, and cardiomyoplasty. When these operative techniques that alter the shape of the left ventricle are utilized, in combination with optimal medical management for heart failure, survival is improved and patients can avoid or postpone transplantation.

Intracoronary adenovirus-mediated delivery and overexpression of the beta(2)-adrenergic receptor in the heart : prospects for molecular ventricular assistance

BACKGROUND

Genetic modulation of ventricular function may offer a novel therapeutic strategy for patients with congestive heart failure. Myocardial overexpression of beta(2)-adrenergic receptors (beta(2)ARs) has been shown to enhance contractility in transgenic mice and reverse signaling abnormalities found in failing cardiomyocytes in culture. In this study, we sought to determine the feasibility and in vivo consequences of delivering an adenovirus containing the human beta(2)AR cDNA to ventricular myocardium via catheter-mediated subselective intracoronary delivery.

METHODS AND RESULTS

Rabbits underwent percutaneous subselective catheterization of either the left or right coronary artery and infusion of adenoviral vectors containing either a marker transgene (Adeno-betaGal) or the beta(2)AR (Adeno-beta(2)AR). Ventricular function was assessed before catheterization and 3 to 6 days after gene delivery. Both left circumflex- and right coronary artery-mediated delivery of Adeno-beta(2)AR resulted in approximately 10-fold overexpression in a chamber-specific manner. Delivery of Adeno-betaGal did not alter in vivo left ventricular (LV) systolic function, whereas overexpression of beta(2)ARs in the LV improved global LV contractility, as measured by dP/dt(max), at baseline and in response to isoproterenol at both 3 and 6 days after gene delivery.

CONCLUSIONS

Percutaneous adenovirus-mediated intracoronary delivery of a potentially therapeutic transgene is feasible, and acute global LV function can be enhanced by LV-specific overexpression of the beta(2)AR. Thus, genetic modulation to enhance the function of the heart may represent a novel therapeutic strategy for congestive heart failure and can be viewed as molecular ventricular assistance.

Partial left ventriculectomy: sunrise or sunset?

Partial left ventriculectomy (PLV) was proposed as an alternative to cardiac transplantation for patients with advanced heart failure. Patients with dilated cardiomyopathy that were considered eligible candidates for cardiac transplantation were offered the option of surgical ventriculectomy or to continue waiting for a donor organ. Sixty-two patients underwent PLV between May 1996 and December 1998, mean age 54 years, 47 males, mean ejection fraction 13.5%, mean peak oxygen consumption 10.8 ml/kg/min, 39% NYHA class III and 61% NYHA IV. Perioperative mortality 3.2%, 10/62 (16%) required implant of a left ventricular assist device (LVAD) due to shock, most in the early post-operative period. Survival at 1 and 2 years was 78% and 68%. Event free survival (freedom from death, LVAD, or return of NYHA class IV failure) was 50% and 37% at 1 and 2 years. Event free survivors experienced improvement in NYHA class (3.7 to 2.2) and increased oxygen consumption (11.7 to 16.0 ml/kg/min). Based on these data PLV has a significant early failure rate and a 2 year event free survival rate of only 37%. PLV does not yield outcomes equivalent to cardiac transplantation based on current selection criteria and requires further investigation to determine its role in the treatment of advanced heart failure.

Surgical treatment of dilated cardiomyopathy with conventional techniques

OBJECTIVE

We review our surgical experience using different conventional surgical techniques in the surgical treatment of the dilated cardiomyopathy (DCMP) in non-transplant eligible patients.

METHODS

In this series we included patients who fit the following criteria: ejection fraction < 35%; end diastolic volume > or = 110 ml/m2; enlargement of the base of the heart (maximal mitral diameter > or = 22 mm/m2) with functional mitral regurgitation; mitral surgery to be performed in every case. Moreover, two groups were considered. (A) Normal or moderately impaired right ventricular function; PAP < 45 mmHg; elective or semielective surgery. (B) Severely impaired right ventricular function; PAP > or = 45 mmHg; severe organ failure; dependency on IABP and/or inotropes; need of ICU stay. From January 1990 to September 1998, 66 patients underwent isolated mitral valve surgery (n = 30); in the remaining 36 the Batista operation (n = 21) or exclusion of akinetic areas (n = 15) were associated. The etiology was ischemic in 42, idiopathic in 23 and post-valvular in one.

RESULTS

When isolated mitral valve surgery was performed, early mortality in group A (n = 22) was 0, in group B (n = 8) 50%. Overall 5-year survival was 70.0 +/- 8.4. in group A 81.8 +/- 8.2, and in group B 37.5 +/- 17.1. When the Batista operation was performed, early mortality in group A (n = 13) was 23.1%, in group B (n = 8) 75%. Overall 2-year survival was 42.9 +/- 10.8 in group A 61.5 +/- 13.5 and in group B 25.0 +/- 15.3. When akinetic areas were excluded, early mortality in group A (n = 11) was 18.2% and in group B (n = 4) 100%. Overall 1-year survival was 53.3 +/- 12.9, in group A 72.7 +/- 13.4.

CONCLUSION

Group A patients have better results in every cohort of patients considered. Even if patients selection seems to be the most important variable for early mortality and late survival, isolated mitral valve surgery, when feasible, provides the best early and late results.

[Functional mitral regurgitation. Physiopathology and impact of medical therapy and surgical techniques for left ventricle reduction]

Functional mitral regurgitation is frequently observed in the setting of left ventricular dyfunction. This finding is a marker of poor outcome in patients with either ischemic or dilated cardiomyopathy. The mechanism accounting for this phenomenon is an altered balance of tethering versus coapting forces acting on the mitral valves in the failing heart. Tethering forces represent an anomalous tension on the mitral valves due to displacement of mitral valve attachments secondary to increased left ventricular chamber sphericity associated with systolic ventricular dysfunction. On the other hand, coapting forces are weak and unable to counteract the abnormal tension acting on the mitral valve, which restricts closure and leads to regurgitation. Vasodilators and inotropic drugs are effective in the management of functional mitral regurgitation. Although partial left ventriculectomy or Batista's procedure is still investigational, this new technique seems to provide an optimal control of functional mitral regurgitation and improve functional capacity and survival of some patients with heart failure.

Early experience with partial left ventriculectomy in the Asia-Pacific region

BACKGROUND

We report our early experience with partial left ventriculectomy done by a group of cardiac surgeons in the Asia-Pacific region.

METHODS

Partial left ventriculectomy was done in 48 patients (mean age, 43 years) with advanced symptomatic cardiomyopathy. The origin of cardiomyopathy was idiopathic in 30 patients, valvular in 10, ischemic in 3, peripartum in 3, sarcoidosis in 1, and viral myocarditis in 1. Procedures performed on the mitral valve were repair with Alfieri method in 8 patients, ring annuloplasty in 2, and replacement in 25.

RESULTS

Seventy-seven percent of patients required myocardial support for weaning from cardiopulmonary bypass, and the overall in-hospital mortality rate was 27%. Mean follow up was 6.5 months (range, 1 to 18 months), and patient survival at 1, 3, and 6 months after discharge was 91%, 88%, and 84%, respectively. Sixty-five percent of survivors with idiopathic and valvular disease achieved significant and sustained improvement in ventricular contractility and symptoms, but there were no clear symptomatic benefits from partial left ventriculectomy in patients with cardiomyopathy from other causes. Most cases of late recurrence of heart failure symptoms (90%) appeared to be related to the development of progressive mitral incompetence.

CONCLUSIONS

After partial left ventriculectomy left ventricular function improved in patients with idiopathic and valve related cardiomyopathies. Late deterioration was related to the development of significant mitral valve incompetence postoperatively, hence definitive mitral valve repair or replacement at the time of the partial left ventriculectomy procedure is advised.

Acute cardiovascular changes of partial left ventriculectomy without mitral valve repair

We assessed the acute cardiovascular changes of partial left ventriculectomy (PLV) in a patient with idiopathic dilated cardiomyopathy (IDCM) without mitral regurgitation. Acutely, PLV reduced left ventricular (LV) end-diastolic dimension and volume while increasing LV ejection fraction and cardiac output due to increased HR and SV. Substantial increases in LV filling pressure, possibly due to high LV end-systolic and diastolic elastances, were of concern clinically and the mechanism(s) of change remain unclear. However, one year follow-up showed remarkable improvements in NYHA and VO2 max while maintaining reduced LV volume, increased LVEF, and trivial MR.

Mortality remains high for outpatient transplant candidates with prolonged (>6 months) waiting list time

OBJECTIVES

The study aimed to determine the risk of death or urgent transplant for patients who survived an initial 6 months on the outpatient heart transplant waiting list when criteria emphasizing reduced peak oxygen consumption are used for transplant candidate selection.

BACKGROUND

Waiting time is a key criterion for heart donor allocation. A recent single-center investigation described decreasing survival benefit from transplant for patients who survived an initial 6 months on the outpatient waiting list.

METHODS

Kaplan-Meier survival analyses were performed for 80 patients from the Hospital of the University of Pennsylvania (HUP) listed from July 1986 to January 1991, and 132 patients from Columbia-Presbyterian Medical Center (CPMC) listed from September 1993 to September 1995. Survival from the time of outpatient listing for the entire group (ALL) was compared to subsequent survival from 6 months onward for those patients who survived the initial 6 months after placement on the outpatient list (6M). Both urgent transplant and left ventricular assist device implantation were considered equivalent to death; elective transplant was censored. RESULTS Survival for 6M was not significantly better than ALL at HUP (subsequent 12 months: 60+/-7 vs. 60+/-6% [mean+/-SD]; p = 0.89) nor at CPMC (subsequent 12 months: 60+/-6 vs. 48+/-5%; p = 0.35). Survival for 6M at both centers was substantially lower than survival following transplant from the outpatient list in the United States in 1995.

CONCLUSIONS

When high-risk patients are selected for nonurgent transplant listing, mortality remains high, even among those who survive the initial six months after listing. Time accrued on the waiting list remains an appropriate criterion for donor allocation.

Potential mechanism of left ventricular outflow tract obstruction after mitral ring annuloplasty

OBJECTIVES

The purpose of this study was to explore whether geometric changes that predispose to left ventricular outflow tract obstruction after mitral ring annuloplasty are coupled to subvalvular apparatus disturbances.

METHODS

Radiopaque markers were implanted in sheep: 9 in the ventricle, 1 in the high interventricular septum, 1 on each papillary muscle tip, 8 around the mitral anulus, 4 on the anterior mitral leaflet, and 2 on the posterior leaflet. One group served as control (n = 5); the others were randomized to undergo annuloplasty with the Duran ring (n = 6; Medtronic, Inc, Minneapolis, Minn) or Carpentier-Edwards Physio ring (n = 6; Baxter Healthcare Corp, Irvine, Calif). After a 7- to 10-day recovery period, 3-dimensional marker coordinates were measured with biplane videofluoroscopy.

RESULTS

At the beginning of ejection, (1) the anterior leaflet was displaced toward the left ventricular outflow tract; (2) the normal atrially flexed anterior anulus was flattened into the left ventricular outflow tract; (3) the posterior anulus was displaced toward the left ventricular outflow tract; (4) the anterior papillary muscle was displaced septally; and (5) the posterior papillary muscle was dislocated inwardly toward the anterior papillary muscle in the Physio ring group compared with the control group. During ejection, all these structures moved septally, encroaching further on the left ventricular outflow tract. In the Duran ring group, only the posterior anulus was displaced toward the left ventricular outflow tract; the anterior leaflet was not displaced toward the left ventricular outflow tract, and it did not move septally during ejection.

CONCLUSIONS

The semirigid Physio ring was associated with perturbations in annular dynamics that caused changes in papillary muscle geometry. We propose an integrated valvular-subvalvular mechanism to explain displacement of the anterior leaflet into the left ventricular outflow tract after mitral ring annuloplasty.

Mitral valve repair for isolated prolapse of the anterior leaflet: an 11-year follow-up

OBJECTIVE

Mitral valve insufficiency (MVI) because of involvement of the anterior mitral leaflet may pose additional risks for late outcome after mitral valve repair, because of more complex techniques. We retrospectively reviewed our experience in patients operated on for isolated anterior mitral leaflet prolapse approached by various techniques.

METHODS

Between 1986 and 1997, 616 patients underwent mitral valve repair at our Institution. Isolated pathology of the anterior mitral leaflet was the cause of MVI in 84 patients (13.6%). Age ranged from 23 to 74 years (mean 50 +/- 14). Etiology of MVI was predominantly degenerative (57 patients, 67.8%), and the mechanism of the regurgitation was mainly due to a chordal rupture (58 patients, 69%). Annular dilatation was present in 75 patients (89.5%). A variety of surgical techniques were applied including chordal shortening (five patients, 5.9%), chordal transposition (three patients, 3.5%), artificial chordae (11 patients, 13%). Since 1992, however, the majority of procedures was performed using the 'edge to edge' technique (52 patients, 51.9%). Annular dilatation was treated mainly by means of a prosthetic ring (46 patients, 61.3%) whereas 18 patients (24%) underwent posterior annuloplasty using gluteraldehyde-treated native pericardium.

RESULTS

Follow-up ranged from 3 to 122 months (mean 46 +/- 24 months). There were three hospital deaths (3.5%) and five late deaths (5.9%) for a Kaplan-Meier estimated survival of 87.6% at 8 years. Three patients underwent early reoperation within 30 days (3.5%), and six patients underwent late reoperation (7.1%), for a cumulative freedom from reoperation of 85.4% at 8 years. Seventy-four percent of the survivors (50 patients) are still in New York Heart Association Class I, and 92% of survivors (62 patients) have no or trivial (1+) residual mitral regurgitation at echocardiographic follow-up.

CONCLUSION

In spite of the greater complexity, conservative surgery to correct anterior mitral valve prolapse pertains high success rate of long term. Recent technical modifications ('edge-to-edge' technique) may allow more expeditious and reproducible procedures with expected favorable influence of mitral valve repair applicability.

Left ventricular volume reduction for end-stage heart disease

Partial left ventriculectomy (PLV) was recently introduced for end-stage dilated cardiomyopathy to improve ventricular function. Since November 1996 we have performed PLV in 14 patients; preoperatively 4 patients had idiopathic dilated cardiomyopathy and 10 had ischemic dilated cardiomyopathy. 57.1% of patients were in New York Heart Association functional Class IV. The mitral valve was replaced in 11 patients. Postoperative echocardiography showed a reduction of left end-diastolic diameter (55.4 +/- 5.4 mm) and an increase in forward ejection (cardiac index from 2.19 +/- 0.571 min/m2 to 2.67 +/- 0.931/min/m2). The 30-day mortality was 28.6% and 20-month survival was 57.2%. Only one patient was not in NYHA functional class due to postoperative progressive mitral incompetence. Prognostic factors should be identified to avoid early failure. However, even if the mortality rate for PLV high, this operation is a valid choice for the treatment of end-stage dilated cardiomyopathy.

Restoring the remodeled enlarged left ventricle: experimental benefits of in vivo porcine cardioreduction in the beating open heart

Conceptual models have been used to assess the efficacy of cardioreduction (i.e., Batista procedure) because in vivo models were not available. This study reproduces an experimental angiographic model of heart failure by placing a large pericardial patch to sphericalize the left ventricle. Patch removal restored an elliptical normal cardiac shape. Cardioreduction was evaluated in 20 mini-pigs on cardiopulmonary bypass. Myocardial protection with a beating open method was used and cardioplegia was not used. Studies were made after an LV incision (i.e., circumflex marginal artery occlusion with the Batista incision). A large pericardial patch sphericalized the left ventricle, and LV closure by patch removal restored normal cardiac shape (ellipse). Ventricular function was evaluated by inscribing Starling curves to fill the heart systolic elastance (Ees, conductance catheter), and surface echocardiogram for fiber shortening. After defining LV function in normal hearts on bypass only, an LV incision to divide the median ramus circumflex artery was made. This ventriculotomy reduced stoke work (SW) 37% +/- 4%, but did not change elastance (Ees) or SW/end-diastolic volume (EDV) significantly. Using the LV incision function as control, patch placement reduced SW 33% +/- 4%, Ees 40% +/- 3%, and SW/EDV 44% +/- 7% and decreased fiber shortening 43% +/- 5% by echocardiogram. Patch removal restored stroke work, SW/EDV, and Ees, and echocardiograms returned to normal values after LV incision. Ventricular function after patch removal was unchanged when the beating open cardioprotective technique was used. We conclude that sphericalization of left ventricular dimensions by pericardial patch placement causes cardiac failure that is relieved by restoring the ellipsoid shape by patch removal. These findings support the value of restoration of an elliptical shape by surgical cardioreduction, when the beating open ventricle is used for myocardial protection.

Partial left ventriculectomy in patients with dialated failing ventricle

BACKGROUND

While partial left ventriculectomy (PLV) improves left ventricular energetic efficiency, concomitant reduction in mitral regurgitation may improve ventricular function.

METHODS

Two hundred ninety-five patients undergoing lateral ventricular wall excision between the papillary muscles (lateral PLV) and 101 patients with an additional excision of papillary muscles and mitral valve replacement (extended PLV) were compared with 65 patients undergoing excision of anterior wall or ventricular aneurysm (anterior PLV).

RESULTS

All patients had reduced functional capacity, New York Heart Association (NYHA) Class III to IV (3.62+/-0.49). Etiologies were cardiomyopathy (37.3%), coronary artery disease (32.3%), valvular disease (19.7%), Chagas' disease (7.8%), and others (2.8%). Patients undergoing lateral and extended PLV had cardiomyopathy as the primary cause of heart failure, while a majority of anterior PLV patients had ischemic disease. Associated procedures included mitral valvuloplasty or replacement (lateral PLV 67%, extended PLV 100%, anterior PLV 40%) and tricuspid annuloplasty (67%, 76%, 28%, respectively.) In each group after surgery, end-systolic dimension decreased more than end-diastolic dimension despite reduced mitral regurgitation. Although extended PLV resulted in greater volume reduction and less mitral regurgitation, these patients had delayed recovery and poor survival. Patients with valvular disease had the most advanced myocardial hypertrophy with the best survival, while those with Chagas' disease had more severe myocarditis, interstitial fibrosis, and the poorest survival.

CONCLUSION

Lateral PLV improved hemodynamics and functional capacity as much as aneurysmectomy by reducing ventricular volume and mitral regurgitation. Inclusion and exclusion criteria have to be sought to make PLV safer and more effective.