Effects of partial left ventriculectomy on left ventricular performance in patients with nonischemic dilated cardiomyopathy

Left ventricular volume reduction surgery: The 4th International Registry Report 2004

BACKGROUND AND METHODS

An international registry of left ventricular volume reduction (LVVR) procedures, including partial left ventriculectomy, has been expanded, updated, and refined to include 568 cases voluntarily reported from 52 hospitals in 12 countries.

RESULTS

Gender, age, ventricular dimension, ethnology, myocardial mass, presence or absence of mitral regurgitation, as well as transplant indication, had little effect on event-free survival, which was defined as either absence of death or ventricular failure requiring mechanical assist or transplantation. Poor preoperative patient condition such as New York Heart Association classification IV, depressed contractility and decompensation requiring an emergency procedure were associated with reduced event-free survival. Other risk factors included an early surgery date, lack of experience, dilated cardiomyopathy as the underlying pathology and extended myocardial resection. Performance of LVVR reached a peak by 1998, but was largely abandoned by 2001, except in Asia, where experienced institutes continue to perform it in patients in better condition with preserved myocardial contractility.

CONCLUSION

Avoidance of risk factors appears to have contributed to the recent survival improvement and may help stratify patients for LVVR. While performance has been decreasing, the concept has been extended to other LVVR and less invasive procedures, which are now under clinical trials.

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.

Semiquantitative histomorphometric analysis of myocardium following partial left ventriculectomy: 1-year follow-up

BACKGROUND

Although partial left ventriculectomy (PLV) may have beneficial clinical effects in patients with dilated cardiomyopathy (DCM), there are no reports on effects of PLV on myocardial histology. The objective of this study was to assess histological properties of the LV myocardium 1 year following PLV as compared to histology at the time of the operation.

METHODS

The study group consisted of 15 consecutive PLV survivors, predominantly male (13/15), aged 45+/-12 years. Surgical specimens and endomyocardial biopsies, taken 12 months postoperatively, were processed routinely and stained with Masson-trichrome. The following morphometric parameters were assessed semiquantitavely: (1) degree of hypertrophy and attenuation; (2) nuclear evidence of hypertrophy; (3) myofibrillar volume fraction; (4) degree of degenerative vacuolar changes; and (5) fibrosis volume fraction.

RESULTS

Both New York Heart Association (NYHA) functional class and ejection fraction (EF) improved 12 months following surgery as compared to preoperative values (2.40+/-0.69 vs. 3.33+/-0.49, p<0.001, and 33.21+/-12.05% vs. 20.21+/-9.07%, p<0.001, respectively). Morphometric analysis demonstrated postoperative decrease in the degree of attenuation as compared to preoperative values (1.40+/-0.51 vs. 2.47+/-0.64, p<0.01), as well as a decrease in fibrosis volume fraction (2.07+/-0.80 vs. 2.67+/-0.49, p<0.001) and nuclear hypertrophy (1.27+/-0.46 vs. 1.67+/-0.62, p<0.05). On the other hand, postoperative increase in myofibrillar volume fraction (1.87+/-0.61 vs. 1.40+/-0.61, p<0.01) was noted.

CONCLUSION

One year postoperatively, PLV has favourable effects on myocardial morphology that parallels improvement in the patient's functional status and LV systolic function.

Plication of the free wall of the left ventricle in dogs with doxorubicin-induced cardiomyopathy

OBJECTIVE

To evaluate plication of the free wall of the left ventricle, which reduces the left ventricular area and volume, as a method to improve the left ventricular systolic function without cardiopulmonary bypass.

ANIMALS

8 mixed-breed adult dogs.

PROCEDURE

Dilated cardiomyopathy (DCM) was induced in each dog by administration of doxorubicin (30 mg/m2, i.v., q 21 d for 168 days). Two dogs died during induction of cardiomyopathy. Plication surgery was performed in 4 dogs. Two dogs did not ondergo to surgery (control group). Values for cardiac output (CO), 2-dimensional and M-mode echocardiography, arterial blood pressure, electrocardiography, blood cell counts, and serum biochemical analyses were recorded after induction of DCM (baseline) and 1, 2, 7, 15, 21, 30, 60, 90, 120, 150, and 180 days after plication surgery. Ambulatory ECG (Holter) recordings were conducted for 24 hours on the day of surgery.

RESULTS

1 dog died after plication surgery. The remaining dogs undergoing ventricular plication had a significant improvement in CO, ejection fraction, and fractional shortening and reductions of left ventricular area and volume after surgery. Electrocardiographic and Holter recordings revealed premature ventricular complexes, which resolved without treatment during the first week after surgery. Clinical condition of the control dogs declined, and these 2 dogs died approximately 40 days after induction of cardiomyopathy.

CONCLUSIONS AND CLINICAL RELEVANCE

Plication of the free wall of the left ventricle improved left ventricular systolic function in dogs with doxorubicin-induced cardiomyopathy. Additional studies are needed to evaluate its application in dogs with naturally developing DCM.

Ventricular reconstruction surgery for congestive heart failure

The significant increase in the prevalence of heart failure in the United States has made this disease a major health problem. The continued shortage of donor organs has prevented heart transplantation from becoming an effective solution for the treatment of end-stage heart failure, and as a result, surgical treatments for heart failure have been reexamined. Surgical therapies represent the evolution of conventional operations, such as coronary artery bypass surgery, and the application of the more novel left ventricular (LV) reconstruction operations which address the geometry of the LV, the important component in the failing heart.

Echocardiographic assessment of regional ventricular function after device-based change of left ventricular shape

We assessed the effects of implantation of Myosplint (Myocor, Maple Grove, Minn), a device that changes left ventricular (LV) cross-sectional shape from circular to bilobar, on regional LV function. A total of 10 open-chest dogs with tachycardia-induced cardiomyopathy were studied before and after Myosplint implantation. LV cross-sectional epicardial echocardiography at the papillary muscle level was performed along with acquisition of hemodynamic data. LV normalized thickening, fractional thickening, end-diastolic thickness, and end-diastolic curvatures were calculated for 10 LV segments. Myosplint implantation did not affect LV hemodynamics, but decreased average end-diastolic curvature (P <.0001) and increased its segmental heterogeneity (P <.0001). There was no change in average fractional thickening, whereas normalized thickening increased (P =.05). In contrast, segmental heterogeneity of both normalized and fractional thickening increased (P =.02 and P =.01, respectively). Structural modeling confirmed that Myosplint implantation increases regional stress heterogeneity and curvature heterogeneity. LV cross-sectional shape markedly affects regional LV performance.

Partial left ventriculectomy--The Third International Registry Report 2002

BACKGROUND

An international registry of partial left ventriculectomy (PLV) has been expanded, updated, and refined to include 440 cases voluntarily reported from 51 hospitals in 11 countries.

RESULTS

Gender, age, ventricular dimension, etiology, ethnology, myocardial mass, operative variation or presence or absence of mitral regurgitation as well as transplant indication had no effects on event-free survival, which was defined as either absence of death or ventricular failure requiring ventricular assist device or listing for transplantation. Preoperative patient condition such as NYHA functional class IV, depressed contractility, and decompensation requiring an emergency procedure were associated with reduced event-free survival. Other risk factors included early date of surgery, lack of experience, and extended myocardial resection. Performance of PLV reached a peak by 1998 and was largely abandoned by 2000 except in Asia, where experienced institutes continue to perform PLV in patients in better condition with preserved myocardial contractility.

CONCLUSION

Avoidance of delineated risk factors appears to improve recent survival and may help stratify high- or low-risk patients for PLV. An integrated approach with mechanical and biological circulatory assist may improve prognosis for patients with dilated failing hearts. While frequency of PLV has decreased, the concept of ventricular volume reduction has been extended to other volume reduction procedures and less invasive procedures now under clinical trial.

Long-term results after partial left ventriculectomy

BACKGROUND

Long-term clinical, echocardiographic and hemodynamic effects after partial left ventriculectomy (PLV) and predictors of outcome have been determined.

METHODS

Between January 1995 and July 1999, PLV was performed in 39 patients. In 15 patients the etiology of heart failure was idiopathic dilated cardiomyopathy (DCMP), 19 patients had ischemic cardiomyopathy (ICMP) and five patients had valvular cardiomyopathy. Concomitant procedures included coronary artery bypass grafting in 16 patients, mitral valve repair in 33 patients and aortic valve replacement in five patients. All patients belonged in New York Heart Association (NYHA) functional class III or IV. Mean follow-up was 663+/-514 days. Clinical, echocardiographic and hemodynamic assessments and metabolic stress testing were performed preoperatively, within 30 days postoperatively and 6, 12 and 24 months after the operation.

RESULTS

Actuarial survival was 64% after 1 year, 55% after 2 years and 44% 3 years after the operation. In patients with ICMP as well as in patients with DCMP actuarial 1 year survival was 60%. At 2-year follow-up NYHA functional class was improved significantly (P<0.05), but LV ejection fraction, LV end-diastolic diameter, cardiac index and peak oxygen consumption did not differ significantly from preoperative values. Analysis of factors influencing postoperative outcome indicated that decreased left ventricular wall thickness and a failure to increase the stroke volume index as a response to preoperative dobutamine administration were associated with postoperative mortality.

CONCLUSIONS

PLV is associated with considerable postoperative mortality and lacking long-term improvement of cardiac performance.

Surgical restoration of the failing left ventricle

As life expectancy increases in the Western world, heart failure (HF) is a major public health concern. Many patients with markedly reduced left ventricular ejection fraction can survive for years with reasonable functional capacity. Transplant-listed patients (LV) with ischemic heart disease who do not receive a donor organ may have a 3- to 4-year survival that equates with those transplanted. Thus, it is difficult to decide when to commit a patient with ischemic cardiomyopathy to transplantation unless supported by a LV assist device for cardiogenic shock. At the same time, the availability of donor organs is decreasing, with only 2000 per year in the United States and less than 300 in the United Kingdom. Consequently, there is a need to evaluate new surgical options for the deteriorating HF patient.

Surgical treatment of congestive heart failure

Cardiac transplantation is the definitive surgical treatment for patients with severe left ventricular dysfunction and congestive heart failure. Unfortunately, however, the supply of donor hearts remains severely limited, so transplantation is an option for only a minority of these patients. Even after being approved for a heart transplant, patients often have a long wait until a suitable donor heart can be found. This waiting period entails a significant mortality rate. Because the supply of donor hearts is not expected to increase, surgeons have introduced several alternatives to heart transplantation, including partial left ventriculectomy, mitral valve repair, myocardial revascularization, and endoventricular circular patch plasty. For maximal benefit, surgeons must refine the selection criteria for determining which patients are the best candidates for each of these procedures.

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.

Evaluation of predictors of clinical outcome after partial left ventriculectomy

BACKGROUND

Outcome after partial left ventriculectomy (PLV) is difficult to predict. Our goal was to determine if clinical measurements including exercise testing could predict outcome after PLV.

METHODS

Sixteen patients with dilated cardiomyopathy had left ventricular ejection fraction, left ventricular end-diastolic diameter, amount of mitral regurgitation (MR), New York Heart Association (NYHA) functional class, and cardiopulmonary exercise testing measurements measured before PLV and 3 months after PLV. Eleven patients who remained stable after PLV (group 1) were compared with 5 patients who deteriorated after PLV (group 2).

RESULTS

Similar significant improvements were seen in both groups 3 months post-PLV with respect to left ventricular ejection fraction (group 1: 0.136+/-0.037 to 0.212+/-0.046; group 2: 0.139+/-0.042 to 0.179+/-0.073) and left ventricular end-diastolic diameter (group 1: 8.5+/-0.7 to 7.0+/-0.6 cm; group 2: 7.6+/-0.6 to 6.5+/-0.6 cm). The MR grade (1.0+/-0.6 versus 2.5+/-0.6), NYHA functional class (1.5+/-0.31 versus 2.5+/-0.6), and peak oxygen consumption (17.8+/-1.1 versus 12.2+/-2.0) were significantly different in the two groups 3 months after PLV (p < 0.05, analysis of variance).

CONCLUSIONS

Patients that do not show significant improvement in peak oxygen consumption, NYHA class and significant decrease in the amount of MR 3 months after PLV, compared with pre-PLV, are at increased risk of clinically deteriorating.

Partial left ventriculectomy and limited heart transplantation availability

BACKGROUND AND AIM

Partial left ventriculectomy, a novel cardiac volume reduction operation, is applied in countries without a developed heart transplantation program. We sought to determine its impact in our population of patients.

METHODS

Partial left ventriculectomy was performed in 38 patients during the last 4 years. Basic inclusion criteria were nonischemic dilated cardiomyopathy and poor response to medical therapy for heart failure. Hemodynamic evaluation was carried out before and after operation. A modified surgical technique of mitral valve repair and ventricle suturing was applied.

RESULTS

Thirty-day, 6-month, and 2-year survival rates were 82% +/- 7%, 65% +/- 8%, and 61% +/- 9%, respectively. Duration of heart failure symptoms was the only predictor of survival (p = 0.042). A high proportion of noncardiac causes of death was noted. Functional capacity in surviving patients improved at every successive measurement up to 1 year postoperatively.

CONCLUSIONS

The introduction of partial left ventriculectomy in a country with limited heart transplantation availability had a great impact on the management of end-stage heart failure and may represent the only surgical option for some patients. The average cost per patient was substantially lower when compared to heart transplantation.

Intermediate-term results after partial left ventriculectomy for end-stage dilated cardiomyopathy: is there a survival benefit?

BACKGROUND

The mortality of congestive heart failure remains high despite advances in medical therapy. Partial left ventriculectomy (PLV) has been advocated as a surgical alternative for select patients with dilated cardiomyopathy.

METHODS

A prospective clinical trial of PLV for patients with end-stage idiopathic dilated cardiomyopathy was performed. Inclusion criteria were left ventricular end-diastolic diameter (LVEDD) greater than 7 cm, refractory New York Heart Association (NYHA) Class IV symptoms, and severely depressed exercise oxygen consumption.

RESULTS

Twenty patients underwent PLV with mean follow-up of 21.1 months. Sixteen were male; mean age was 50.1 years +/- 12.0 years (range 25-67 years). Left ventricle (LV) ejection fraction improved after surgery from 14.1% +/- 4.7% to 24.1% +/- 3.1% (p < 0.05, t-test) and this improvement persisted up to 3 years after operation. LVEDD and NYHA Class also were notably improved. There were two early deaths for an operative mortality of 10% (2 of 20 patients). Nine patients after initial improvement in clinical status and LV function developed worsening congestive heart failure (CHF). Six of the 9 ultimately died of complications secondary to CHF. One-, 2-, and 3-year survival rates were 84%, 64%, and 40%, respectively, by Kaplan-Meier analysis. The other three patients required listing for transplantation because of recurrent NYHA Class IV symptoms. Freedom from death or the need for listing for transplantation at 1, 2, and 3 years was 65%, 53%, and 33%, respectively. The remaining nine patients all had improvement in their NYHA classification.

CONCLUSIONS

PLV can be performed with acceptable early and intermediate term mortality; survival compares favorably to reports of similar groups of patients treated with medical therapy alone.

Partial left ventriculectomy. The First Japanese Registry Report 1999

OBJECTIVE

Partial left ventriculectomy has been performed without standardized inclusion/exclusion criteria. A registry has been established to accumulate experience with this procedure to identify indications, risks and benefits.

METHODS

In response to a mailed inquiry, 90 cases were voluntarily registered from 28 Japanese institutions.

RESULTS

Males (n = 67, 74.4%) predominated, and 29 (32.2%) patients were over 60 years old. The underlying cardiac pathologies included dilated cardiomyopathy (n = 75, 83.3%), valvular disease (n = 8, 8.9%), the dilated phase of hypertrophic cardiomyopathy (n = 4, 4.5%), and others (n = 3, 3.3%). Gender, age, etiology, papillary muscle excision and absent transplant indication did not significantly affect survival. Poorer preoperative condition, reduced contraction and decompensation necessitating emergency operation were each associated with a significantly higher risk. Hospitals performing less than 5 cases had poorer results than more experienced institutions (p = .0019), which showed a tendency towards improved survival in the second half of their experience (p = .096). Hospital mortality (n = 29, 32.6%) and late death (n = 10, 11.2%) were mainly from ventricular failure with few sudden deaths over a period of 63.6 patient years follow-up. Late mortality was equally distributed in the first year and leveled off with significantly improved cardiac functional class in survivors.

CONCLUSION

Partial left ventriculectomy was associated with better survival in less symptomatic patients with better contractile reserve undergoing an elective operation preserving the papillary muscles. Avoidance of identified risk factors may allow better patient selection and improved survival in the current environment where rescue transplantation is not readily available. Long-term follow-up is warranted with more registry data.

Spontaneous ventricular arrhythmias following partial left ventriculectomy for nonischemic dilated cardiomyopathy: relation to hemodynamics and survival

The study assessed the value of ambulatory electrocardiogram (AECG) monitoring for identification of patients who are at increased risk for cardiac death or arrhythmic event following partial left ventriculectomy (PLV). Furthermore, the impact of PLV and its hemodynamics on the occurrence of spontaneous ventricular arrhythmias was assessed in long-term survivors. In 32 idiopathic dilated cardiomyopathy patients who underwent PLV, ambulatory ECG (AECG) was performed preoperatively, early postoperatively, and 6 months and 12 months after surgery. In 17 of 19 patients who survived > 12 months after the procedure, left ventricular (LV) angiography was performed at the same time points and was used to calculate LV ejection fraction, and end-diastolic and end-systolic wall stress. During a mean follow-up of 478 +/- 405 days, 11 cardiac events occurred. Cox univariate regression revealed frequency of premature ventricular contractions > 30/hour at baseline (p = 0.0213) and duration of heart failure symptoms (p = 0.0226) as predictors of cardiac death or arrhythmic event after PLV. In a multivariate analysis, only frequency of premature ventricular contractions > 30/hour was a significant predictor. There was no change in the frequency or severity of ventricular arrhythmias after PLV. However, frequency of premature ventricular contractions correlated with LV end-diastolic stress (r = 0.35, p = 0.013), and ejection fraction (r = -0.34, p = 0.016). Preoperative AECG monitoring may help stratification of PLV patients. Serial AECG did not show that PLV influence the incidence or the complexity of spontaneous ventricular arrhythmias. In contrast, it appears that a hemodynamically "successful" procedure may decrease the incidence of ventricular arrhythmias.

Partial left ventriculectomy: the 2nd International Registry Report 2000

BACKGROUND

Partial left ventriculectomy (PLV) has been performed without standardized inclusion or exclusion criteria.

METHODS

An international registry of PLV was expanded, updated, and refined to include 287 nonischemic cases voluntarily reported from 48 hospitals in 11 countries.

RESULTS

Gender, age, ventricular dimension, etiology, ethnology, myocardial mass, operative variation, presence or absence of mitral regurgitation, and transplant indication had no effects on event-free survival, which was defined as absence of death or ventricular failure that required a ventricular assist device or listing for transplantation. Preoperative patient conditions, such as duration of symptoms (> 9 vs < 3 years; p = 0.001), New York Heart Association (NYHA) class (Class IV vs < Class IV; p = 0.002), depressed contractility (fractional shortening [FS] < 5% vs > 12%; p = 0.001), and refractory decompensation that required emergency procedure (p < 0.001) were associated with reduced event-free survival. Five or more cases in each hospital led to significantly better outcomes than the initial four cases. Rescue procedures for 14 patients nonsignificantly improved patient survival (2-year survival 52%) over event-free survival (2-year survival 48%; p = 0.49), with improved NYHA class among survivors (3.6 to 1.8; p < 0.001). Outcome was better in 1999 than in all series before 1999 (p = 0.02) most likely due to patient selection, which was refined to avoid known risk factors such as reduced proportion of patients in NYHA Class IV, FS < 5%, and hospitals with experience in 10 or less cases. A combination of these risk factors could have stratified 17 high-risk patients with 0% 1-year survival and 26 low-risk patients with 75% 2-year event-free survival.

CONCLUSION

Avoidance of risk factors appears to improve survival and might help stratify high- or low-risk patients. Although less symptomatic patients with preserved contractility had better results after PLV, change of indication requires prospective randomized comparison with medical therapies or other approaches.

Partial left ventriculectomy: history, current status, and future role

Whereas discouraging clinical results and lack of scientific evidence decreased the initial interest in partial left ventriculectomy (PLV), factors contributing to success and failure have now been identified by clinical observations, theoretical analyses, and data from an international registry, which are herein reviewed to outline the current status and future role of this procedure as a treatment of heart failure.

Histopathology of resected myocardium and outcome of partial left ventriculectomy

BACKGROUND

Since preoperative hemodynamics are not proven to be a predictor of effects of partial left ventriculectomy (PLV), myocardial histopathology may be better correlated with effects and outcome of PLV.

METHODS

Myocyte size (micron) in the excised myocardium was measured in 338 patients undergoing PLV. Endocardial fibrosis, interstitial fibrosis, and inflammatory cell infiltration were enumerated as none = 0, mild = 1, moderate = 2, and severe = 3. These histopathologic observations were correlated with patients' postoperative survival.

RESULTS

Reduced survival was seen in patients with advanced (> or = moderate) interstitial fibrosis in all patients (n = 338, p = 0.064) and in the subgroup with nonischemic etiology (n = 229, p = 0.0039). Although correlation between endocardial and interstitial fibrosis was significant (r = 0.55, p < 0.01), endocardial fibrosis failed to correlate with postoperative survival. While Chagas' disease was associated with severe inflammation and poor survival, the presence of inflammatory cell infiltration had no effect on survival in all patients combined (p = 0.943). Although most patients (n = 266, 79%) had myocyte diameter over 30 micron, those with less hypertrophy (< 30 micron, n = 70, 21%) had a tendency toward increased survival (p = 0.067) regardless of underlying etiology.

CONCLUSION

Interstitial fibrosis may be an important factor in stratification of patients for repair (PLV) or replacement (transplantation). PLV may be more beneficial in patients with less hypertrophy, before develqpment of interstitial fibrosis. Endomyocardial biopsy might not predict the extent or variation in degree of interstitial fibrosis, which may be better evaluated by other metabolic or perfusion studies that measure overall myocardial histopathology and viability.

Current perspectives of partial left ventriculectomy in the treatment of dilated cardiomyopathy

OBJECTIVES

Partial left ventriculectomy has been performed as an alternative to heart transplantation in the treatment of severe cardiomyopathies. This investigation documents the clinical and left ventricular (LV) function effects of this procedure, associated, when necessary, with mitral insufficiency correction, in 43 patients with idiopathic dilated cardiomyopathy.

METHODS

Eighteen patients were in New York Heart Association class III and 25 in class IV. Seven of them were operated in cardiogenic shock. The procedure was associated with mitral annuloplasty in 32 patients and mitral replacement in three.

RESULTS

Nine patients (20.9%) died during the hospital period and the cause of death was associated with ventricular failure in seven patients. The other patients were followed up from 2 to 57 months (mean, 28.3 months). At 6 months of follow-up, eight patients were in functional class I, 13 in class II, three in class III and one patient was in class IV (P<0.001). On the other hand, nine patients died during the first 6 months and another six in the later postoperative period. The cause of late death was progressive heart failure in eight patients, and seven patients died because of arrhythmia related events. The actuarial survival was 58.1+/-7.5% at 1 year and 43.9+/-8.1% at 4 years of follow-up. Regarding ventricular function modifications, the LV diastolic volume decreased by around 25% and the LV ejection fraction increased from 17.8+/-4.7 to 22.3+/-7.9% (P<0.001), whereas significant changes in the cardiac index, stroke index and pulmonary pressures were also found 1 month after the operation. In the later follow-up, despite the maintenance of hemodynamic improvement, the LV diastolic volume tended to increase and returned to preoperative levels at 4 years, while a concomitant decrease in the LV ejection fraction was also observed.

CONCLUSION

Partial left ventriculectomy associated with mitral insufficiency correction improves LV function and ameliorates congestive heart failure in patients with idiopathic cardiomyopathy. Otherwise, the LV function benefits seem to be restricted by the possibility of progressive LV redilatation. Furthermore, the clinical application of this procedure is limited by the high mortality observed in the first postoperative months and by the possibility of heart failure progression and arrhythmia related events at late follow-up.

Perioperative hemodynamics in patients undergoing partial left ventriculectomy

OBJECTIVES

Effects of partial left ventriculectomy (PLV) were studied by analyzing perioperative hemodynamics with measurements of left ventricular (LV) pressure-volume (PV) relationships and thermodilution catheter measurements in the pulmonary artery.

METHODS

Between July and October 1996, 43 consecutive patients underwent PLV with and without mitral valvuloplasty with a thermodilution catheter and PV loop analysis immediately before and after surgery. Patients were 52+/-13 years and 67+/-13 kg, with reduced functional capacity (New York Heart Association 3.3+/-0.3) due to cardiomyopathy (24), ischemic disease (13), valvular disease (3), and Chagas' disease (3).

RESULTS

PLV required cardiopulmonary bypass for 44+/-24 minutes, with the heart arrested in 10 patients for 26+/-22 minutes for coronary artery bypass grafting (8), aortic valve replacement (2), and autotransplantation (2). Two patients failed to come off bypass, six died in the hospital and 35 (35 [81.4%] of 43) were discharged. Changes in PV loops included decreased end-diastolic and end-systolic volume, resulting in no change in stroke volume. Pulmonary artery wedge pressure decreased despite elevated end-diastolic pressure. Ejection fraction, end-systolic elastance (E-max), afterload recruitable stroke work, and volume intercepts all improved and resulted in similar stroke work with less energy expenditure (less PV area), thus improving myocardial energetic efficiency.

CONCLUSION

Results suggest that PLV improves systolic function but decreases diastolic compliance, which results in reduced net ventricular function immediately after surgery. Thus, immediate hemodynamic improvements appeared to derive from reduced severity in mitral regurgitation and perioperative load manipulation. Improved myocardial energetics may ameliorate LV function and improve the course of underlying myocardial disease.

Functional capacity late after partial left ventriculectomy: relation to ventricular geometry and performance

OBJECTIVES

While partial left ventriculectomy (PLV) may improve functional status, the duration and determinants of this improvement are poorly known. This study sought to assess the relationship between left ventricular (LV) shape and function and functional status in late survivors after PLV for non-ischemic dilated cardiomyopathy (DCM).

METHODS

We assessed the relations between LV shape and function and functional status in 17 consecutive patients who survived >12 months after PLV for non-ischemic DCM. Invasive diagnostic studies were performed before, early after, at mid-term after, and late after PLV. According to their functional status after >12 months of follow-up, patients were divided into responders (n=10) or non-responders (n=7).

RESULTS

After PLV, the LV systolic major-to-minor axis ratio was higher in responders at early, mid-, and late follow-up (P=0.003, P=0.008 and P=0.04, respectively). LV circumferential end-diastolic stress decreased early after PLV, but increased afterwards in non-responders only (P=0.049). LV ejection fraction was similar in the two groups at baseline, and at early and mid-follow-up, but was lower in non-responders at late follow-up (P=0.006). However, LV end-diastolic and end-systolic volumes, and LV end-systolic circumferential stress showed no difference between the two groups.

CONCLUSIONS

It appears that poor functional capacity in late post-PLV survivors is related to postoperative LV geometry.

Acute and short-term effects of partial left ventriculectomy in dilated cardiomyopathy: assessment by pressure-volume loops

OBJECTIVES

The aim of this study was to evaluate the short-term effects of partial left ventriculectomy (PLV) on left ventricular (LV) pressure-volume (P-V) loops, wall stress, and the synchrony of LV segmental volume motions in patients with dilated cardiomyopathy.

BACKGROUND

Surgical LV volume reduction is under investigation as an alternative for, or bridge to, heart transplantation for patients with end-stage dilated cardiomyopathy.

METHODS

We measured P-V loops in eight patients with dilated cardiomyopathy before, during and two to five days after PLV. The conductance catheter technique was used to measure LV volume instantaneously.

RESULTS

The PLV reduced end-diastolic volume (EDV) acutely from 141+/-27 to 68+/-16 ml/m2 (p < 0.001) and to 65+/-6 ml/m2 (p < 0.001) at two to five days postoperation (post-op). Cardiac index (CI) increased from 1.5+/-0.5 to 2.6+/-0.6 l/min/m2 (p < 0.002) and was 1.8+/-0.3 l/min/m2 (NS) at two to five days post-op. The LV ejection fraction (EF) increased from 15+/-8% to 35+/-6% (p < 0.001) and to 26+/-3% (p < 0.003) at two to five days post-op. Tau decreased from 54+/-8 to 38+/-6 ms (p < 0.05) and was 38+/-5 ms (NS) at two to five days post-op. Peak wall stress decreased from 254+/-85 to 157+/-49 mm Hg (p < 0.001) and to 184+/-40 mm Hg (p < 0.003) two to five days post-op. The synchrony of LV segmental volume changes increased from 68+/-6% before PLV to 80+/-7% after surgery (p < 0.01) and was 73+/-4% (NS) at two to five days post-op. The LV synchrony index and CI showed a significant (p < 0.0001) correlation.

CONCLUSIONS

The acute decrease in LV volume in heart-failure patients following PLV resulted at short-term in unchanged SV, increases in LVEF, and decreases in peak wall stress. The increase in LV synchrony with PLV suggests that the transition to a more uniform LV contraction and relaxation pattern might be a rationale of the working mechanism of PLV.

Results of partial left ventriculectomy for dilated cardiomyopathy: hemodynamic, clinical and echocardiographic observations

OBJECTIVES

The study was done to prospectively measure the echocardiographic, hemodynamic and clinical outcomes after partial left ventriculectomy (PLV).

BACKGROUND

Although PLV can improve symptoms of advanced heart failure, immediate postoperative echocardiographic findings remain abnormal.

METHODS

Fifty-nine patients with cardiomyopathy and advanced heart failure underwent PLV and concomitant mitral valve surgery between May 1996 and December 1997. Thirty-nine percent were on inotropic therapy. All were New York Heart Association (NYHA) functional class III or IV. Mechanical circulatory support (LVAD) and transplant were provided for rescue therapy when hemodynamic compromise occurred. Patients were followed for a mean of 405+/-168 days, and clinical, echocardiographic and hemodynamic measures were obtained preoperatively, immediately postoperatively, and at 3 and 12 months prospectively.

RESULTS

Comparing preoperative and 12-month postoperative values in event-free survivors, we found: NYHA functional class improved from 3.6 to 2.1, p < 0.0001; peak oxygen consumption increased from 10.8 to 16.0 ml/kg/min, p < 0.0001; LV ejection fraction increased from 13+/-6.0% to 24+/-6.9%, p < 0.0001; LV end diastolic diameter decreased from 8.2+/-1.03 to 6.2+/-0.64 cm, p < 0.0001, and volume was reduced from 167+/-60 to 105+/-38 ml/m2, p = 0.02. Central hemodynamics did not normalize after surgery.

CONCLUSIONS

Partial left ventriculectomy can provide structural remodeling of the heart that may result in temporary improvement in clinical compensation. However, perioperative failures and the return of heart failure limit the propriety of this procedure.

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.

Partial left ventriculectomy improves left ventricular end systolic elastance in patients with idiopathic dilated cardiomyopathy

OBJECTIVE

To assess the effect of partial left ventriculectomy (PLV) on estimate of left ventricular end systolic elastance (Ees), arterial elastance, and ventriculoarterial coupling.

PATIENTS

11 patients with idiopathic dilated cardiomyopathy before and two weeks after PLV, and 11 controls.

INTERVENTIONS

Single plane left ventricular angiography with simultaneous measurements of femoral artery pressure was performed during right heart pacing before and after load reduction.

RESULTS

PLV increased mean (SD) Ees from 0.52 (0.27) to 1.47 (0.62) mm Hg/ml (p = 0.0004). The increase in Ees remained significant after correction for the change in left ventricular mass (p = 0.004) and end diastolic volume (p = 0.048). As PLV had no effect on arterial elastance, ventriculoarterial coupling improved from 3.25 (2.17) to 1.01 (0.93) (p = 0.017), thereby maximising left ventricular stroke work.

CONCLUSION

It appears that PLV improves both Ees and ventriculoarterial coupling, thus increasing left ventricular work efficiency.

The effect of diastolic stiffness on ventricular function after partial ventriculectomy: a finite element simulation

Partial ventriculectomy (PV) has been proposed by Batista and colleagues to improve cardiac function in patients with dilated cardiomyopathy (DCM); however, results have been mixed. We tested the hypothesis that preoperative diastolic function affects the stroke volume/end-diastolic pressure (Starling) relationship after PV. A previously described finite element simulation of DCM and PV was used. Diastole and end systole were represented by separate elastic finite element models with different unloaded shapes and nonlinear material properties. Left ventricular (LV) end-systolic elastance (E(ES)), diastolic compliance (DC), and Starling relationships were calculated. DC was varied by changing Ogden material property alpha(i) from 12 (compliant) to 20 (stiff). PV was simulated at 20% LV mass reduction. The slope of the Starling relationship increased from 1.82 to 1.21 as alpha(i) increased from 12 to 20. Partial ventriculectomy increased the Starling relationship in each case from 1.34 to 1.01 respectively. However, the net result in each case is a decrement in the Starling relationship with resection, and the smallest decrement was associated with the highest diastolic stiffness (alpha(i) = 20). Partial ventriculectomy depressed the Starling relationship for all values of diastolic compliance. It is expected that patients with a higher diastolic stiffness should do better.

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.

[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.