Flow dynamics of a novel counterpulsation device characterized by CFD and PIV modeling.

BACKGROUND: Historically, single port valveless pneumatic blood pumps have had a high incidence of thrombus formation due to areas of blood stagnation and hemolysis due to areas of high shear stress. METHODS: To ensure minimal hemolysis and favorable blood washing characteristics, particle image velocimetry (PIV) and computational fluid dynamics (CFD) were used to evaluate the design of a new single port, valveless counterpulsation device (Symphony). The Symphony design was tested in 6-h acute (n=8), 5-day (n=8) and 30-day (n=2) chronic experiments in a calf model (Jersey, 76 kg). Venous blood samples were collected during acute (hourly) and chronic (weekly) time courses to analyze for temporal changes in biochemical markers and quantify plasma free hemoglobin. At the end of the study, animals were euthanized and the Symphony and end-organs (brain, liver, kidney, lungs, heart, and spleen) were examined for thrombus formations. RESULTS: Both the PIV and the CFD showed the development of a strong moving vortex during filling phase and that blood exited the Symphony uniformly from all areas during ejection phase. The laminar shear stresses estimated by CFD remained well below the hemolysis threshold of 400 Pa inside the Symphony throughout filling and ejection phases. No areas of persistent blood stagnation or flow separation were observed. The maximum plasma free hemoglobin (<10mg/dl), average platelet count (pre-implant = 473 ± 56 K/µl and post-implant = 331 ± 62 K/µl), and average hematocrit (pre-implant = 31 ± 2% and post-implant = 29 ± 2%) were normal at all measured time-points for each test animal in acute and chronic experiments. There were no changes in measures of hepatic function (ALP, ALT) or renal function (creatinine) from pre-Symphony implantation values. The necropsy examination showed no signs of thrombus formation in the Symphony or end organs. CONCLUSIONS: These data suggest that the designed Symphony has good washing characteristics without persistent areas of blood stagnation sites during the entire pump cycle, and has a low risk of hemolysis and thrombus formations.

HeartMate VE LVAS design enhancements and its impact on device reliability.

OBJECTIVE: The HeartMate VE left ventricular assist system (LVAS) has supported more than 2300 patients and has been shown to be effective for bridge to cardiac transplantation and has demonstrated improved outcomes in survival as a destination therapy. Improvements in device durability are needed as bridge to transplant times increase and as we move into the era of LVAD as destination therapy. The purpose of this study is to determine if design enhancements to the HeartMate LVAS have improved device reliability and durability. METHODS: A retrospective analysis of serious mechanical failures was performed in 1865 devices (1458 VE, 407 XVE). The analysis of data included devices used to support patients from September 1998 for bridge to transplantation and destination therapy. Serious mechanical failures were defined as inflow valve dysfunction, percutaneous lead breaks, diaphragm fractures or punctures, bearing failures, outflow graft erosion and pump disconnects. RESULTS: Median device duration for the VE was 97 days (max 1206 days), and 85 days (max 517 days) for the XVE. A total of 134 serious mechanical failures occurred and included inflow valve dysfunction (5.3% VE, 2.4% XVE) (P = 0.853) percutaneous lead breaks (1.9% VE, 0% XVE) (P < 0.001) diaphragm fractures (0.1% VE, 0% XVE) (P = 0.134) outflow graft erosion (0.2% VE, 0% XVE) (P = 0.1096), pump disconnects (0.1% VE, 0% XVE) (P = 0.1336) and bearing failures (0.6% VE, 0.2% XVE) (P = 0.5538). Of the XVEs 97% were free of serious mechanical failures at 6 months and 82% at 1 year compared to 92 and 73% for the VE, respectively. The 6-month difference between the devices was statistically significant (P = 0.0063) and there was no statistically significant difference at 1 year (P = 0.1492). CONCLUSIONS: Preliminary experience with the HeartMate XVE LVAS demonstrated a significant reduction in percutaneous lead breaks. Early trends indicate positive impact of recent design modifications on XVE performance. These design modifications may improve device durability and reliability, which is crucial as we enter the era of LVADs as an alternative to medical therapy.

Blood lactic acid levels after artificial heart implantation.

The aim of this study is to investigate blood lactic acid levels after the placement of the AbioCor implantable replacement heart to determine whether circulatory support with the AbioCor device results in adequate tissue perfusion. Tissue perfusion may not be adequate during cardiac surgery, especially with the use of cardiopulmonary bypass (CPB). Inadequate perfusion is usually associated with anaerobic metabolism, metabolic acidosis, and lactate accumulation. Ten calves had implantation of the AbioCor by means of a right thoracotomy. Standard cardiopulmonary bypass was performed during surgery. Lactic acid levels and blood gas analyses were measured. All animals were monitored for pressures in the aorta, pulmonary artery, and left and right atria. The output of the AbioCor was calculated based on beat rate and stroke volume. All animals were rapidly weaned off cardiopulmonary bypass to full AbioCor support and had normal hemodynamics with normal filling pressures. The lactic acid levels were elevated after surgery, peaked at 8 to 12 hours, and then gradually decreased to the normal range 24 hours after surgery. There was a positive relationship between lactate levels, oxygen consumption, and extraction rate, that is, the lactic acid levels were higher in the presence of increased oxygen consumption and increased oxygen extraction rate. There was a negative relationship between lactate levels and oxygen delivery, and arterial and venous oxygen content, that is, the lactic acid levels were higher when oxygen delivery and arterial and venous oxygen contents were low. The pathophysiology of lactic acidosis is uncertain, but is most likely due to inadequate perfusion during cardiopulmonary bypass, and lactate washout after adequate perfusion has been established. The return to aerobic metabolism with clearance of lactate demonstrates that the AbioCor is able to provide complete circulatory support with normal tissue perfusion.

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.

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.

Current status of the AbioCor implantable replacement heart.

BACKGROUND: The AbioCor implantable replacement heart (IRH) has been developed as an alternative to transplant (ie, destination therapy). We report our experience with the AbioCor IRH in a bovine model at the University of Louisville. METHODS: Male Holstein cows were used (85 to 115 kg). The internal controller, battery, and secondary transcutaneous energy transfer coil were implanted in the right flank. After cardiopulmonary bypass, the thoracic unit was implanted orthotopically. After removal of air and weaning from cardiopulmonary bypass, the AbioCor was connected to internal components and energy transfer through transcutaneous energy transfer coils was achieved. RESULTS: Nineteen animals underwent implantation of the AbioCor IRH for a proposed 30-day duration. There were 6 deaths, none related to device malfunction. All animals demonstrated normal hemodynamics with normal pressures in the aorta, pulmonary artery, left atrium, and right atrium. There was no significant hemolysis and all animals demonstrated normal end organ function. The internal battery allowed for brief periods of untethered mobility. CONCLUSIONS: The AbioCor IRH has resulted in normal hemodynamics and normal end organ function without evidence of hemolysis in a bovine model.

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.

Initial experience with the AbioCor implantable replacement heart at the University of Louisville.

Potential benefits of heart transplantation are limited by the severe donor organ shortage. The AbioCor implantable replacement heart has been developed as a potential alternative to heart transplantation. We report our initial experience with the AbioCor in a bovine model. A right thoracotomy was performed for access to the heart and great vessels. After initiation of cardiopulmonary bypass, excision of the native ventricles was followed by orthotopic placement of the IRH and complete implantation of the transcutaneous energy transfer coil, controller, and battery pack. Invasive monitoring of IVC, SVC, carotid artery, pulmonary artery, and left atrial (LA) pressures was performed in all animals. Twelve calves have undergone implantation of the AbioCor. There were three early deaths, one from bleeding, one from respiratory failure, and one from neurodysfunction from low flow during CPB. Nine animals have had a normal recovery and survived a mean of 24.5 days (range, 4-48 days). All the animals have demonstrated excellent hemodynamics with the maintenance of normal pressures in the LA, SVC, IVC, pulmonary artery, and aorta. Adjustment of the right-sided internal hydraulic fluid shunt has allowed for control of right-left balance and, thereby, manipulation of left and right side filling pressures. Late morbidity has consisted of neck wound infection and sepsis, pneumonia, and bleeding. Successful orthotopic implantation of all components of the AbioCor has been achieved in a bovine model. This device has demonstrated restoration of normal hemodynamics and excellent function of the atrial hydraulic shunt to achieve right-left balance.

Clinically available extracorporeal assist devices.

Mechanical circulatory support has been shown to be of benefit to allow recovery after conventional heart surgery and as a successful bridge to heart transplantation. Recent clinical trials with implantable left ventricular assist devices (LVADs) have been completed with these devices showing restoration of normal hemodynamics and successful bridge to transplantation. A major advantage of the implantable devices is the ability for the patient to be discharged and followed up at an outpatient setting. However, multiple advantages to extracorporeal devices still remain, which are the focus of this review. One advantage of the extracorporeal devices is that they can be placed in much smaller patients than currently available implantable LVADs. Also, because of differences in design of the assist devices, the extracorporeal devices can be placed without the need for the cardiopulmonary bypass and with decreased operative time and dissection. Perhaps the biggest advantage of the extracorporeal devices is that they can provide a support for both the right and left side of the heart as opposed to the implantable LVADs, which are only used as left ventricular assist devices. This article describes in detail the advantages and disadvantages of the extracorporeal devices as well as the operative techniques used to implant them. As the number of patients with heart failure continues to rise, so will the need for mechanical circulatory support. Though the majority of these patients will be served by a long-term implantable device, there will remain a subset of patients that will be best suited for treatment with extracorporeal devices.

Transmyocardial laser revascularization combined with coronary artery bypass grafting: a multicenter, blinded, prospective, randomized, controlled trial.

OBJECTIVE: We sought to assess the safety and efficacy of transmyocardial revascularization combined with coronary artery bypass grafting in patients not amenable to complete revascularization by coronary bypass alone. METHODS: A total of 263 patients whose standard of care was coronary artery bypass grafting and who had one or more ischemic areas not amenable to bypass grafting were prospectively randomized to receive coronary bypass of suitable vessels plus transmyocardial revascularization to areas not graftable (n = 132) or coronary bypass alone with nongraftable areas left unrevascularized (n = 131). Group preoperative demographics and operative characteristics were similar. RESULTS: The operative mortality rate after coronary bypass/transmyocardial revascularization was 1.5% (2/132) versus 7.6% (10/131) after coronary bypass alone (P =.02). Patients undergoing both coronary bypass and transmyocardial revascularization required less postoperative inotropic support (30% vs 55%, P =.0001) and had a trend toward fewer insertions of intra-aortic balloon pumps (4% vs 8%, P =.13) than did patients having coronary bypass alone. Multivariable predictors of operative mortality were coronary artery bypass alone (odds ratio, 5.3; 95% confidence interval, 1.1-25.7; P =.04) and increased age (odds ratio, 1.1; 95% confidence interval, 1. 0-1.2; P =.03). One-year Kaplan-Meier survival (95% vs 89%, P =.05) and freedom from major adverse cardiac events defined as death or myocardial infarction (92% vs 86%, P =.09) favored the combination of coronary bypass and transmyocardial revascularization. Baseline to 12-month improvement in angina and exercise treadmill scores was similar between groups. CONCLUSIONS: In a prospective, randomized, multicenter trial, transmyocardial revascularization combined with coronary artery bypass grafting in patients not amenable to complete revascularization by coronary bypass alone was safe; however, angina relief and exercise treadmill improvement were indistinguishable between groups at 12 months of follow-up. Operative and 1-year survival benefits observed after adjunctive transmyocardial revascularization require confirmation by a larger validation study, which is ongoing.

Different responses of human anti-HLA and anti-alphagal antibody to long-term intravenous immunoglobulin therapy.

Concentrated human immunoglobulin (IVIG) has been administered intravenously in the treatment of autoimmune disorders and to reduce anti-HLA antibodies in highly sensitized patients awaiting organ transplantation. It has also been shown, in experimental animals, to prevent the hyperacute rejection of discordant xenografts, possibly by anticomplement activity. The aim of the present study was to assess the effect of IVIG therapy on both acquired anti-HLA antibodies and natural antigalactose alpha1-3 galactose (alphaGal) antibodies in five patients awaiting heart transplantation. Five patients placed on mechanical circulatory support who had developed high HLA panel-reactive antibodies (PRA) or in whom the percentage of PRA was increasing rapidly were treated weekly with 500 mg/kg IVIG, which contained 1% of anti-alphaGal IgG. Levels of PRA, anti-alphaGal IgG and IgM, and serum cytotoxicity to pig cells were measured before, during, and after therapy. PRA percentages in the five patients were initially 85%, 53%, 23%, 19% and 19% (mean 39%). Mean PRA fell by 66% after 3 months of therapy (to a mean PRA of 14%), and by 96% after 6 months therapy (to a mean PRA of 2%). Anti-alphaGal antibody levels and serum cytotoxicity to pig aortic endothelial cells did not change significantly. These results confirm the effectiveness of IVIG therapy in reducing PRA in HLA highly sensitized patients. It is likely that IVIG does not contain the relevant anti-HLA antibody, resulting in an accelerated catabolism of native alloantibodies. However, as IVIG contains a normal level of anti-alphaGal IgG, catabolism of anti-alphaGal IgG is not modified, as it is being continuously replaced. To achieve a decrease in the anti-alphaGal IgG level it would be necessary to use IVIG depleted of this antibody.

Comparison of transmyocardial revascularization with medical therapy in patients with refractory angina.

BACKGROUND: Transmyocardial revascularization involves the creation of channels in the myocardium with a laser to relieve angina. We compared the safety and efficacy of transmyocardial revascularization performed with a holmium laser with those of medical therapy in patients with refractory class IV angina (according to the criteria of the Canadian Cardiovascular Society). METHODS: In a prospective study conducted between March 1996 and July 1998 at 18 centers, 275 patients with medically refractory class IV angina and coronary disease that could not be treated with percutaneous or surgical revascularization were randomly assigned to receive transmyocardial revascularization followed by continued medical therapy (132 patients) or medical therapy alone (143 patients). RESULTS: After one year of follow-up, 76 percent of the patients who had undergone transmyocardial revascularization had improvement in angina (a reduction of two or more classes), as compared with 32 percent of the patients who received medical therapy alone (P<0.001). Kaplan-Meier survival estimates at one year (based on an intention-to-treat analysis) were similar for the patients assigned to undergo transmyocardial revascularization and those assigned to receive medical therapy alone (84 percent and 89 percent, respectively; P=0.23). At one year, the patients in the transmyocardial-revascularization group had a significantly higher rate of survival free of cardiac events (54 percent, vs. 31 percent in the medical-therapy group; P<0.001), a significantly higher rate of freedom from treatment failure (73 percent vs. 47 percent, P<0.001), and a significantly higher rate of freedom from cardiac-related rehospitalization (61 percent vs. 33 percent, P<0.001). Exercise tolerance and quality-of-life scores were also significantly higher in the transmyocardial-revascularization group than in the medical-therapy group (exercise tolerance, 5.0 MET [metabolic equivalent] vs. 3.9 MET; P=0.05); quality-of-life score, 21 vs. 12; P=0.003). However, there were no differences in myocardial perfusion between the two groups, as assessed by thallium scanning. CONCLUSIONS: Patients with refractory angina who underwent transmyocardial revascularization and received continued medical therapy, as compared with similar patients who received medical therapy alone, had a significantly better outcome with respect to improvement in angina, survival free of cardiac events, freedom from treatment failure, and freedom from cardiac-related rehospitalization.

Vascular delay of the latissimus dorsi provides an early hemodynamic benefit in dynamic cardiomyoplasty.

OBJECTIVES: Dynamic cardiomyoplasty (CMP) as a surgical treatment for chronic heart failure improves functional class status for most patients. However, significant hemodynamic improvement with latissimus dorsi muscle (LDM) stimulation has not been consistent. The current protocols do not allow early LDM stimulation after CMP surgery. We hypothesized that vascular delay of LDM would increase myocardial assistance after CMP and allow early (48-h) LDM stimulation after CMP. METHODS: Mongrel dogs (n = 24) were divided in four groups: 1) controls (n = 6), single-stage CMP; 2) Group ES (n = 6), single-stage CMP with early LDM stimulation beginning 48 h, postoperatively; 3) Group VD (n = 6), vascular delay of the LDM followed by CMP without early LDM stimulation, and 4) Group VDES (n = 6), vascular delay of LDM (14-18 days), followed by CMP with early stimulation (48 h postoperatively). Two weeks after CMP, global cardiac dysfunction was induced by injecting microspheres into the left coronary artery. LDM-assisted (S) beats were compared with nonstimulated beats (NS) by measuring aortic pressure (AoP), LV pressure, aortic flow, and by calculating first derivative of LV contraction (+/-dP/dt), stroke volume (SV), and stroke work (SW). RESULTS: In ES, LDM stimulation had no effect on the hemodynamic parameters. In the other groups, LDM stimulation significantly (p < 0.05) increased AoP, LVP, dP/dt, SV, and SW. However, these increases were much larger in VD and VDES. In VD, LDM stimulation increased peak AoP by 21.5+/-3.8 mm Hg, LVP by 22.1+/-4.1 mm Hg, dP/dt by 512+/-163 mm Hg/sec, SV by 10.4+/-2.3 mL, and SW by 22.1+/-5.4 g/m(-1). Similarly, in VDES, LDM stimulation increased peak AoP by 24.1+/-4.7 mm Hg, LVP by 26.2+/-4.3 mm Hg, dP/dt by 619+/-47 mm Hg/sec, SV by 6.5+/-0.7 mL, and SW by 16.7+/-4.1 g/m(-1). CONCLUSIONS: In dogs with global LV dysfunction, CMP after vascular delay resulted in a significant improvement in hemodynamic function measured 2 weeks after surgery. This improvement was not provided by single-stage CMP with or without early stimulation. Vascular delay of the LDM before surgery may play an important role for early benefit after CMP, shorten the overall muscle training period, as well as increase hemodynamic response to LDM stimulation.

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.

Results after partial left ventriculectomy versus heart transplantation for idiopathic cardiomyopathy.

OBJECTIVE: Partial left ventriculectomy has been introduced as an alternative surgical therapy to heart transplantation. We performed a single-center, retrospective analysis of all patients with idiopathic dilated cardiomyopathy who underwent partial left ventriculectomy or heart transplantation or who were listed for transplantation to determine operative mortality rate, 12-month survival, freedom from death on the heart transplantation waiting list, and freedom from death or need for relisting for heart transplantation. METHODS: Patients who had partial left ventriculectomy (October 1996 to April 1998) were retrospectively compared with patients who were listed for heart transplantation (January 1995 to April 1998). Survival was assessed after the surgical procedure (partial left ventriculectomy vs heart transplantation) and from time of listing for heart transplantation to assess the additional impact of waiting list deaths. Freedom from death or relisting for heart transplantation was also compared. RESULTS: There was no difference in age or United Network for Organ Sharing status between the 2 groups. Twenty-nine patients with idiopathic dilated cardiomyopathy were listed for heart transplantation; 17 patients underwent transplantation, 6 patients died while on the waiting list, and 6 patients remain listed. One patient died after heart transplantation, and 1 patient required relisting. Sixteen patients had partial left ventriculectomy; 10 patients are in improved condition, 2 patients died (1 death early from sepsis and 1 death from progressive heart failure), and 4 patients required relisting for heart transplantation. Operative survival was 94% after partial left ventriculectomy and 94% after heart transplantation (P =.92). Postoperative 12-month Kaplan-Meier survival was 86% after partial left ventriculectomy and 93% after heart transplantation (P =.90). Twelve-month Kaplan-Meier survival after listing for heart transplantation was 75% due to death while on the waiting list (P =.76). Freedom from death or need for relisting for heart transplantation was 56% after partial left ventriculectomy and 86% after transplantation (P =.063). CONCLUSION: Operative and 12-month survival after partial left ventriculectomy and heart transplantation were comparable. However, despite their initial improvement, many patients who underwent partial left ventriculectomy required relisting for transplantation. Although partial left ventriculectomy is associated with acceptable operative and 12-month survival, it may prove to serve better as a bridge to transplantation in patients with idiopathic dilated cardiomyopathy rather than definitive therapy, given the number of patients who required relisting for transplantation.

Intermediate-term results of partial left ventriculectomy.

Partial left ventriculectomy (PLV) has been introduced as an option for patients with end-stage dilated cardiomyopathy. We report the result of a prospective trial of PLV in patients with idiopathic dilated cardiomyopathy, left ventricular end-diastolic diameter (LVEDD) > 7 cm, refractory New York Heart Association (NYHA) Class IV symptoms, and depressed exercise oxygen consumption studies. Sixteen patients underwent a PLV with a mean follow-up of 13 months. Fourteen patients were male. Mean age was 49.6+/-10.5 years (range 30 to 67 years). Left ventricular ejection fraction (LVEF) improved after surgery from 13.9+/-5.6 to 21.0+/-8.4, and this improvement persisted for up to 12 months after operation. LVEDD and NYHA Class also were significantly improved after surgery and for up to 12 months of follow-up. Operative mortality was 6.25%. Twelve-month survival was 86% by Kaplan-Meier analysis. Four (25%) of 16 patients that had initial improvement after PLV developed recurrent heart failure and were listed for transplantation. Freedom from need for listing for heart transplantation was 65% at 12 months. Freedom from death or the need for relisting at 12 months was 56%. PLV can be performed with acceptable early and 12-month mortality. Significant improvements in LVEF, LVEDD, and NYHA Class are seen at up to 12 months of follow-up. Some patients will develop recurrent heart failure and require relisting for heart transplantation.

Intraoperative assessment of acute hemodynamic changes after partial left ventriculectomy.

Partial left ventriculectomy (PLV) has been introduced as an alternative surgical therapy for patients with end-stage dilated cardiomyopathy. The physiological benefits of PLV are relatively unknown. Therefore, the objective of this study was to determine the acute effects of PLV by measuring cardiac function before and after PLV. Aortic and left ventricular pressures and aortic flow were measured in eight patients. Continuous, beat-to-beat data were recorded and compared pre-PLV and post-PLV with and without inferior vena cava (IVC) occlusions. PLV increased cardiac output (0.93+/-0.5, p = 0.01) as a result of increased stroke volume (5.12+/-4.24, p = 0.06) and heart rate (14.5+/-8.44, p = 0.02). Contractility (+/- dP/dt, 240.33+/-74.28, p = 0.001) and external work (650.8+/-320.4, p = 0.01) were also improved. Left ventricular end-diastolic elastance (0.15+/-0.14, p = 0.10) nearly doubled after PLV. Our results indicated an improved cardiac function as measured by increased cardiac output, stroke volume, ejection fraction (EF), and contractility.

Transmyocardial revascularization in patients with refractory, unstable angina.

BACKGROUND: Previous reports of transmyocardial revascularization (TMR) indicate a significant mortality in patients with refractory, unstable angina. We hypothesized that TMR with a holmium laser would result in significant angina relief with acceptable mortality in this patient population. METHODS AND RESULTS: Patients were defined as unstable if they were unweanable from intravenous antianginal medications or were too unstable for a persantine thallium scan. Patients had a left ventricular ejection fraction (LVEF) of > 25% and were not amenable to CABG or PTCA. Before treatment, all patients had class IV angina. TMR was performed in 85 patients, with a mean of 35 +/- 11 transmural laser channels. Mean age was 63 +/- 10 years. Mean LVEF was 48 +/- 11%. Of these patients, 79% were men. Prior CABG and/or PTCA had been performed in 87% of patients, and 72% of patients had a history of prior MI. Operative mortality was 12% (10 of 85). There were 2 deaths between discharge and 3 months after surgery and 7 late deaths from 6 to 12 months after surgery. Twelve-month mortality was 22.4% (19 of 85). At 3 months, 86% of patients had class II angina or better. At 6 and 12 months, 77% and 75% of patients, respectively, had class II angina or better. Mean angina class at 6 and 12 months' follow-up was 1.5 +/- 1.1 and 1.6 +/- 1.3, respectively. CONCLUSIONS: In patients with refractory unstable angina, TMR with a holmium laser provided significant angina relief. Moreover, 30-day operative mortality and 12-month mortality were acceptable, especially given this subset of unstable patients with refractory angina.

Transmyocardial revascularization utilizing a holmium:YAG laser.

OBJECTIVE: To evaluate the efficacy of transmyocardial revascularization performed on patients with refractory class IV or unstable angina with a holmium:yttrium-aluminum-garnet laser. METHODS: Transmyocardial revascularization with a holmium:yttrium-aluminum-garnet laser was performed in 42 patients with refractory angina who were not candidates for percutaneous transluminal coronary angioplasty or coronary artery bypass grafting. Patients had either Canadian Heart Association class IV angina (n = 23) or unstable angina (n = 19) and were unable to be weaned from intravenous nitroglycerin. Preoperative thallium studies identified the extent and location of reversible ischemia. Operative exposure was via a limited left anterior thoracotomy. An average of 45+/-11 laser channels were created with a mean operative time of 106+/-38 min. RESULTS: Perioperative mortality was 12% (5/42) with no late deaths. Complications included ventricular 7.1% (3/42) and atrial 4.7% (2/42) arrhythmias, reoperation for chest-wall hemorrhage 2% (1/42), and respiratory failure requiring reintubation 2% (1/42). Intra-aortic balloon pump placement was required in 12% (5/42). The mean postoperative length of stay was 5.5+/-4.9 (1-25) days. Mean follow-up on 100% of patients is 5.4+/-3.0 (1-12) months. At 3 (n = 33) and 6 (n = 21) months follow-up the mean angina class was 1.5+/-0.1 (P < 0.002) and 1.1+/-0.1 (P < 0.001), respectively. CONCLUSIONS: Transmyocardial revascularization utilizing a holmium:yttrium-aluminum-garnet laser resulted in a significant reduction in angina class and was beneficial in patients with refractory angina untreatable by conventional methods.