Acute cardiovascular changes of partial left ventriculectomy without mitral valve repair

Organ-saving surgical alternatives to treatment of heart failure

Over time, various surgical treatment strategies have evolved to manage advanced heart failure (HF). Scientific and technological breakthroughs through the last 50 years have put forward various surgical alternatives to patients with advanced HF encompassing surgical ventricular restoration to surgical gene therapy and stem cell replacement of the diseased ventricles. Organ-saving surgical options which used to be promising included dynamic cardiomyoplasty, partial resection of ventricle and cardiac wrapping with Acorn CorCap cardiac support device. These procedures were eventually abandoned due to negative outcomes and without proven disadvantages. Another organ-saving surgical option currently being considered but still make little sense is cardiac regeneration by stem cell therapy, i.e., cardiomyocyte restoration and replacement. Presently, the organ-saving surgical alternatives to treat end-stage HF are revascularization for ischemic cardiomyopathy, mitral valve surgery (repair or replacement) for ischemic mitral incompetence (IMI), left ventricular (LV) aneurysmectomy (surgical ventricular restoration) and mitral valve repair for IMI. These aforementioned procedures have become quite established approaches and with increasing experience are continuously being modified to improve outcome. Various mechanical circulatory support systems have emerged over time to improve functional status of patients with advanced HF, either as a bridge to heart transplantation or as a bridge to myocardial recovery. Likewise offered in those with contraindications to transplantation. Ventricular assist devices (VAD) can keep patients alive until an eventual transplantation. This article reviews the variety of the myriad of alternative organ-saving surgical alternatives that have been available or are currently available provided to patients with end-stage HF, their advantages and deficiencies, as well as prospects in HF therapy.

Partial left ventriculectomy

Batista introduced the partial left ventriculectomy (PLV), which is based on physics alone. With experience, it has been found that the extent of myocardial disease and viability of retained muscle is an important determinant of early and late survival. Although the PLV has been almost abandoned in many countries following the negative message from the Cleveland Clinic, it is still alive in Japan with a refined concept, surgical technique and patient selection. In a series of 63 patients undergoing PLV for idiopathic dilated cardiomyopathy since 1996, operative mortality was 9.5%, and 1-, 3- and 5-year survival rates were 71.1%, 56.2% and 45.9%, respectively. Improved survival has obtained by using appropriate patient selection and concomitant restrictive mitral annuloplasty (1-, 3- and 5-year survival rate =86.5%, 78.6% and 59.4%, respectively, in the most recent 33 patients). Because of insufficient availability of donors for heart transplantation, nontransplant cardiac surgery for medically refractory heart failure is important. Ventricular restoration procedures, including PLV, should be seriously considered as an important option for endstage heart failure.

Immediate Functional Effects of Left Ventricular Reduction: A Doppler Echocardiographic Study in the Rat

BACKGROUND

Immediate functional effects of left ventricle reduction (LVR) are not yet fully defined. Those effects have been studied in the experimental model of myocardial infarction scar plication (MISP) in the rat.

METHODS AND RESULTS

A Doppler echocardiogram was performed immediately before and after MISP in 20 rats with infarction of the left ventricle (LV) larger than 40%. LV diastolic volume reduction (475 +/- 114 versus 185 +/- 65 muL) was accompanied by heart rate decrease (230 +/- 25 versus 166 +/- 27 beats/min) and increase of ejection fraction (37 +/- 7 versus 67 +/- 12%), fractional shortening (18 +/- 3 versus 46 +/- 8%) and posterior wall shortening velocity (1.50 +/- 0.62 versus 2.01 +/- 0.46 cm/s). LV diastolic volume/stroke volume slope was steeper after LVR, suggesting enhancement of the Frank-Starling mechanism. Restrictive pattern of left atrial emptying was alleviated after LVR (E wave: 101 +/- 15 versus 66 +/- 14 cm/s; E/A ratio: 6.8 +/- 2.9 versus 5.0 +/- 2.2; E wave deceleration time: 36 +/- 6 versus 51 +/- 10 msec) even though left atrial diameter (0.69 +/- 0.07 versus 0.66 +/- 0.06 cm) and A wave (18.0 +/- 9.4 versus 15.8 +/- 7.8 cm/s) did not vary. Additionally, a pulmonary flow profile suggesting pulmonary hypertension was observed in 12 of 17 animals before, and in only 3 after, LVR.

CONCLUSION

LVR favors cardiac function not only by reducing afterload. The present data are in consonance with previous suggestions that the Frank-Starling mechanism is enhanced after MISP and, in addition to LV ejection function improvement, the unprecedented facilitation of left atrial emptying after LVR was particularly noteworthy. Even though LVR restricts ventricular distensibility, atrial emptying can be facilitated, probably on account of LV ejection improvement.

A surgical approach to severe congestive heart failure--overlapping ventriculoplasty

BACKGROUND

Previously we developed a new procedure of overlapping cardiac volume reduction (OLCVR) surgery for patients with dilated cardiomyopathy refractory to medical treatment. Papillary muscle plication (PMP) when combined with OLCVR may achieve a better clinical outcome.

PURPOSE

To investigate the early and intermediate results of OLCVR with or without PMP.

METHODS

Twenty-five patients (21 males, 4 females, aged 60 +/- 13 years) with either ischemic (n = 7) or nonischemic (n = 18) dilated cardiomyopathy underwent either isolated OLCVR (n = 11; Original Group) or PMP combined with OLCVR (n = 14; Integrated Group).

RESULTS

Early deaths occurred in two (8%) from a noncardiac cause and late deaths in six, two from a cardiac and four from a noncardiac cause. Postoperative data in survivors were significantly improved in terms of NYHA functional class (from 3.6 +/- 1.9 to 1.6 +/- 1.1), ejection fraction (from 18 +/- 6% to 31 +/- 8%), left ventricular diastolic dimension (from 73 +/- 9 to 65 +/- 6 mm), and left ventricular end-diastolic volume index (from 194 +/- 81 to 128 +/- 43 mL/m2) (p < 0.05) in selected comparative cases. One-year crude and cause-specific survivals were 70.9% and 83.1%, respectively, at a mean follow-up of 12.8 months. One-year crude survival of the Integrated and Original Group was 85.7% and 55.6%, respectively (p = 0.24).

CONCLUSIONS

Although limitations exist in evaluating operative results, we consider OLCVR to be a relatively safe and effective procedure for selected patients with dilated cardiomyopathy. The addition of PMP to OLCVR may enhance the elliptic formation of left ventricle shape and improve mitral valve tethering, but further study is mandatory.

Partial left ventriculectomy and mitral valve repair: favorable short-term results in carefully selected patients with advanced heart failure due to dilated cardiomyopathy

BACKGROUND

Because of the scarcity of donor hearts, surgical alternatives to heart transplantation, such as partial left ventriculectomy (PLV), were introduced for treatment of advanced heart failure. Here, we report our experience with this procedure performed in combination with mitral valve repair.

METHODS

Twelve patients with dilated cardiomyopathy (DCM), New York Heart Association (NYHA) class exceeding III on maximal medical therapy, cardiac index of 2.5 liter/min/m2 or less, VO2max of 14 ml/kg/min or less, left ventricular end-diastolic diameter (LVEDD) of 7.0 cm or more, and grade II or greater mitral incompetence, were selected for PLV and mitral valve reconstruction (MVR). Echocardiography, hemodynamics, spiroergometry, and clinical assessment were performed before and 1 year after the operation.

RESULTS

One-year survival was 83.3%. All 10 surviving patients were free from failure of the procedure 1 year post-operatively. From pre-operatively to 1 year post-operatively, NYHA functional class improved from 3.3 +/- 0.3 to 1.9 +/- 0.2 (p < 0.001), cardiac index increased from 2.0 +/- 0.2 liter/min/m2 to 2.9 +/- 0.2 liter/min/m2 (p < 0.001), stroke volume index from 25.9 +/- 4.8 ml/m2 to 40.3 +/- 7.3 ml/m2 (p = 0.008), and VO2max from 10.9 +/- 2.4 ml/kg/min to 16.0 +/- 3.6 ml/kg/min (p = 0.016), whereas LVEDD decreased from 8.4 +/- 0.6 cm to 6.6 +/- 0.3 cm (p < 0.001), left ventricular end-systolic diameter from 6.8 +/- 0.8 cm to 5.3 +/- 0.5 cm (p < 0.001), and mitral incompetence from 2.4 +/- 0.6 to 0.9 +/- 0.6 (p < 0.001). Pulmonary pressures and fractional shortening did not change significantly (p > 0.05). Four patients received an implantable cardioverter/defibrillator as a result of their pathologic electrophysiologic examination.

CONCLUSIONS

In carefully selected patients, PLV combined with MVR achieves short-term results comparable to that after heart transplantation. However, long-term results and multicenter evaluation will be needed to define its place in the treatment of advanced heart failure.

Partial left ventriculectomy in modified adriamycin-induced cardiomyopathy in the dog

BACKGROUND

The purpose of this study was to evaluate modified adriamycin-induced cardiomyopathy in the dog for research on partial left ventriculectomy (PLV).

METHODS

An intracoronary catheter was introduced into the left main stem via the first marginal branch in a retrograde fashion in 12 adult foxhound dogs. The catheter was connected to a percutaneous access port that was used for weekly adriamycin administration (10 mg over a 1-hour period on 5 occasions). Follow-up examinations (transthoracic echocardiography, hemodynamic parameters, cardiopulmonary status, neurohormones) were done before, 1 week after the last adriamycin administration, and then 6 weeks later. This protocol was performed in 6 dogs (control group: Group 1). The other 6 dogs underwent PLV 1 week after the last adriamycin administration (Group 2). After the last measurements, all dogs were killed with saturated potassium chloride under general anesthesia and the hearts were excised for histologic examination. All data were calculated as mean and standard error of the mean. Differences were calculated by the Wilcoxon signed-rank test for paired and unpaired data. p < 0.05 was considered statistically significant.

RESULTS

One dog from each group died suddenly during adriamycin administration (probably due to ventricular arrhythmia). In addition, 1 dog from Group 2 suffered from a severe systemic inflammatory response syndrome after PLV and died 36 hours after surgery. Thus, 5 dogs from Group 1 and 4 from Group 2 underwent the entire study protocol. Adriamycin administration resulted in a severe dilated cardiomyopathy that was comparable in both groups (significant increase of central venous pressure, mean pulmonary artery pressure, pulmonary wedge pressure, left ventricular end-systolic and end-diastolic diameters, oxygen extraction, troponin I and anti-diuretic hormone, whereas cardiac output, ejection fraction and venous oxygen saturation decreased significantly). Deterioration of cardiac function continued after termination of adriamycin administration in Group 1 dogs, albeit not as progressively as during adriamycin administration. In contrast, cardiac function improved in Group 2 dogs after PLV, but did not reach baseline values. Cardiac index increased and oxygen extraction (p = 0.03) decreased, resulting in an enhanced venous oxygen saturation (p = 0.02). In particular, the distance of the papillary muscles at end diastole (p = 0.02) and at end systole (p = 0.02) at the mid-papillary level decreased significantly after PLV, resulting in reduced left ventricular diameter and volume (statistically significant for left ventricular end-systolic diameter and volume). All hearts had severe histologic alterations characteristic of adriamycin-induced toxicity, including cytoplasmic vacuolation, myocyte degeneration and increased fibrosis.

CONCLUSION

Modified adriamycin-induced cardiomyopathy in the dog may be suitable for research on PLV.

Myocardial infarction scar plication in the rat: cardiac mechanics in an animal model for surgical procedures

BACKGROUND

The immediate effects of surgical reduction of left ventricle cavity on cardiac mechanics have not been well defined.

METHODS

Cardiac mechanics were analyzed before and after myocardial infarction scar plication in 11 isolated infarcted rat hearts.

RESULTS

Despite a decrease in myocardial stiffness, an increase in chamber stiffness was noted after myocardial infarction scar plication. Systolic function was favored in more than one way. For the same diastolic pressures, maximal developed pressures were higher after myocardial infarction scar plication, and the slope of the systolic pressure-volume relationship was steeper afterwards as compared with before; this means that Frank-Starling recruitment is accentuated in smaller cavities. In addition, the developed net forces needed to generate these pressures were clearly lower afterward than before, indicating reduced ventricular afterload.

CONCLUSIONS

The study results show that diastolic function is harmed and systolic function is favored by myocardial infarction scar plication. We suggest that preoperative evaluation of the degree of diastolic dysfunction and impairment of the Frank-Starling mechanism may help to identify patients who may have a poor postoperative outcome due to diastolic or systolic dysfunction.

Mitral valve reconstruction in the patient with heart failure

Secondary MR is a complication of end-stage cardiomyopathy and is associated with a poor prognosis and is due to progressive mitral annular dilation and alteration in LV geometry. A vicious cycle of continuing volume overload, ventricular dilation, progression of annular dilation, increased LV wall tension and worsening MR and CHF occur. The mainstay of medical therapy is diuretics and afterload reduction, and is associated with poor long-term survival in these patients with CHF and MR. However, surgical intervention in the form of undersized, 'overcorrecting' mitral valve repair has shown great promise and is an area of ongoing investigation.

Partial left ventriculectomy for dilated cardiomyopathy: is this an alternative to transplantation?

OBJECTIVE

To determine the late effectiveness of partial left ventriculectomy and risk factors for failure.

METHODS

Between May 1996 and December 1998, partial left ventriculectomy and concomitant mitral valve surgery were performed in 62 patients (95% transplant candidates) with a mean age of 54 years (range 17-72 years). All patients were in New York Heart Association functional class III (38%) or IV (62%) because of idiopathic dilated cardiomyopathy (59 patients) or ischemic, valvular, or familial cardiomyopathy (1 patient each). Outcomes considered for multivariable analysis included implantation of left ventricular assist device, return to class IV heart failure, relisting for transplantation, and death.

RESULTS

Partial left ventriculectomy reduced the left ventricular end-diastolic diameter immediately preoperatively to immediately postoperatively (from 8.4 +/- 1.1 cm to 5.92 +/- 0.8 cm; P =.01), reduced the left ventricular end-diastolic volume index (from 133 +/- 48.6 mL to 64.1 +/- 26 mL; P <.0001), and increased the left ventricular ejection fraction (from 16 +/- 7.6 to 31.5 +/- 10.9; P <.0001). Survival was 80% and 60% at 1 and 3 years after surgery and freedom from failure was 49% and 26%, respectively. Increased systolic pulmonary artery pressure, decreased maximum exercise oxygen consumption, and increased left atrial pressure were associated with failure and/or death. The degree of preoperative mitral regurgitation did not correlate with clinical outcome.

CONCLUSIONS

Early and late failures preclude the widespread use of partial left ventriculectomy. However, in view of its sometimes beneficial effect, use in situations that do not allow for transplantation or as a biologic bridge to transplantation may be appropriate.