Isolated bypass grafting of the left internal thoracic artery to the left anterior descending coronary artery: late consequences of incomplete revascularization

OBJECTIVE

Multiple strategies to achieve some degree of myocardial revascularization are available. In some, less complete revascularization is accepted to limit invasiveness. To examine the issues of incomplete revascularization, we assessed the long-term impact of additional non-left anterior descending coronary artery stenoses in patients undergoing only grafting of the left internal thoracic artery to the left anterior descending coronary artery.

METHODS

A total of 2067 patients underwent primary isolated grafting of the left internal thoracic artery to the left anterior descending coronary artery from 1971 to 1997. Of these, 26% and 13% had 2- and 3-system disease, respectively. Multivariable analyses of survival and reintervention were performed in the hazard function domain for 27,683 patient-years of follow-up (mean 14 +/- 6.7).

RESULTS

Survival was 99%, 88%, and 62% at 1, 10, and 20 years. Right coronary artery or left circumflex system disease of 50% or more (P =.02) and particularly high-grade (>/=70%) left circumflex (P =.01) and proximal right coronary artery disease (P =.01), as well as any degree of left main trunk stenosis (P <.0001), were associated with reduced long-term survival. Compared with 75% 20-year survival in patients with no non-left anterior descending disease, those with either left circumflex or left main trunk disease experienced a 44% survival, and those with proximal right coronary artery disease, 42%. The most common stated reason for incomplete revascularization was small vessel size. Freedom from reintervention was 89% and 65% at 10 and 20 years, respectively. High-grade left main trunk disease, but, in contrast, mid or distal disease of the right coronary artery, and not left circumflex disease, were risk factors for reintervention.

CONCLUSIONS

These findings call into question the long-term appropriateness of interventions whose strategy includes leaving unrevascularized segments in territories not in the distribution of the left anterior descending coronary artery.

Clinical experience with long-term use of implantable left ventricular assist devices: indications, implantation, and outcomes

We describe our clinical experience with 205 implantable left ventricular assist devices at the Cleveland Clinic between December 1991 and January 2000, along with manufacturers' data submitted to the Food and Drug Administration. In patients with end-stage cardiac failure who are suitable candidates for transplantation, these devices serve as excellent bridges to transplantation. Recent modifications have increased pump reliability and reduced thromboembolic rates. The vented electric HeartMate (Thermocardiosystems Inc, Woburn, MA) and the Novacor (Baxter-Novacor, Oakland, CA) left ventricular assist systems allow patients to be discharged from the hospital while awaiting a donor heart. Experience with long-term support is providing insights into permanent implantation of these devices as destination therapy. Although infection remains a major impediment to long-term support, patient-pump interactions leading to changes in the coagulation and immune systems are being recognized, and these interactions may have important implications with respect to thromboembolism, infection, and sensitization to human leukocyte antigens (HLAs). Better understanding of these factors may eventually lead to the development of permanently implantable pumps as an alternative to transplantation.

Clinically available intracorporeal left ventricular assist devices

There are now 3 commercially approved intracorporeal left ventricular assist devices (LVADs). Product similarities include (1) LV apex, to pump, to ascending aorta flow patterns, (2) excellent hemodynamic support with reversal of heart failure and neurohormone/cytokine milieu, and (3) the requirement of major surgery for device implantation and later explantation, with or without transplant. Two electrically powered models allow a tether-free existence and hospital discharge. All complications are being addressed, and in the past decade, device failure and thromboemboli have been reduced. Infection continues to be an obstacle to more widespread adoption of therapy. Despite pre-LVAD shock, most patients (65% to 78% by Food and Drug Administration data) survive until transplant (averaging 80 to 96 days of LVAD support), and posttransplant survival is equal to nonbridged patients. As the problem of infection is reduced, more widespread LVAD use can be anticipated.

Long-term effectiveness of operations for ascending aortic dissections

OBJECTIVE

To evaluate long-term effectiveness of a strategy for managing the aortic root and distal aorta according to the pathology in ascending aortic dissection.

METHODS

From 1978 to 1995, 208 patients underwent operations for acute (n = 135) and chronic (n = 73) ascending aortic dissection. Surgical strategies included valve resuspension with supracoronary aortic root repair and ascending aortic graft for normal sinuses and valve (n = 135), composite valve and ascending aortic graft for abnormal sinuses and valve (n = 47), and valve replacement and supracoronary ascending aortic graft for normal sinuses and abnormal valve (n = 26). Resection extended into the arch only if the intimal tear originated in or extended to the aortic arch (n = 31).

RESULTS

Hospital mortality was 14%. Cardiogenic shock (P =.002) and concomitant coronary artery bypass grafting (P =.001) were associated with increased risk; use of circulatory arrest (P =.0003) decreased risk. Survival was 87%, 68%, and 52% at 30 days, 5 years, and 10 years, respectively. Advanced age, earlier date of operation, composite graft, and arch resection were associated with decreased survival; residual distal dissected aorta was not. Reoperation was required for 5 proximal and 8 distal problems.

CONCLUSIONS

In both acute and chronic ascending aortic dissections, (1) circulatory arrest is associated with low early mortality; (2) with normal sinuses and valve, supracoronary repair of the dissected aortic root and valve resuspension is effective long term; and (3) residual distal dissected aorta does not decrease late survival and has a low risk of aneurysmal change and reoperation for at least 10 years.

The clinical significance of flow cytometry crossmatching in heart transplantation

OBJECTIVE

Flow cytometry crossmatching (FCXM) is more sensitive than the cytotoxic crossmatch in identifying preformed antibodies to donor alloantigens, but its clinical importance is controversial. The objective of this study was to determine the association of a FCXM with survival and incidence of vascular rejection in cardiac transplant recipients with a negative cytotoxic crossmatch.

METHODS

Between 1993 and 1998, 357 heart transplant recipients with a negative T cell cytotoxic crossmatch were studied by three-color FCXM to quantitate anti-donor IgG reactions against B and T lymphocytes. Reactions positive against both were consistent with human leukocyte antigen (HLA) Class I reactivity, and those against B cells only were considered to be against HLA Class II antigens. Endpoints were episodes of vascular rejection, death from acute and chronic rejection and overall survival.

RESULTS

Fifty patients were FCXM for Class I-positive, 144 for Class II-positive, and 163 were negative. At 1 month, freedom from vascular rejection was 64% in Class I patients, but 90% and 96% in Class II or negative crossmatch patients (P<0.0001). Survival of the negative crossmatch group was higher than either Class I or II groups (94%, 74% and 76%, respectively, at 3 years; P<0.0001). Death from acute rejection was 3% and 2% at 3 years in negative or Class II-positive patients, but 19% in Class I patients (P<0.0001). Death from chronic rejection occurred only in Class II patients (P=0.002).

CONCLUSIONS

Despite a negative T-cell cytotoxic crossmatch, a positive flow cytometry crossmatch correlates with important clinical events after heart transplantation.

Ineffectiveness and potential proarrhythmia of atrial pacing for atrial fibrillation prevention after coronary artery bypass grafting

BACKGROUND

Atrial pacing is often used empirically to suppress atrial ectopy and prevent atrial fibrillation after coronary artery bypass grafting.

METHODS

To determine whether atrial overdrive pacing reduces atrial fibrillation and atrial ectopy after coronary artery bypass grafting, 100 patients were randomized to no atrial pacing (Control) versus AAI pacing at 10 beats/min or more above the resting heart rate (Paced), started by postoperative day 1 and continued through day 4. Major end points were new atrial fibrillation and frequency of atrial ectopy during the first 4 days after coronary artery bypass grafting.

RESULTS

Atrial fibrillation occurred by day 4 in 13 of 51 (25.5%) Paced and in 14 of 49 (28.6%) Control patients, p = 0.90. Control patients who developed atrial fibrillation had significantly more atrial ectopy than those who did not. Atrial ectopy was paradoxically more frequent in the Paced group (2,106+/-428 versus 866+/-385 per 24 hours, p = 0.0001). Loss of capture, sensing, and consistent atrial pacing occurred frequently during atrial pacing.

CONCLUSIONS

Contrary to prevailing opinion and practice, postoperative atrial overdrive pacing significantly increases atrial ectopy and does not reduce the likelihood of atrial fibrillation.

Mitral valve surgery in patients with severe left ventricular dysfunction

OBJECTIVES

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Risk factors and outcomes after coronary reoperation in 739 elderly patients

BACKGROUND

As second coronary artery bypass graft (CABG) operations are becoming more common in elderly patients, we conducted a retrospective analysis of risk factors for in-hospital and late outcome in patients aged 70 and over.

METHODS

We reviewed records of 739 patients who underwent second CABG at age 70 or older at our institution between 1983 and 1993. Preoperative, operative, and postoperative variables were analyzed to identify predictors of in-hospital and long-term mortality.

RESULTS

The mean age (+/- standard deviation) at reoperation was 74 +/- 3 years and the mean interval after primary operation was 130 +/- 55 months. In-hospital mortality was 7.6% (n = 56). Preoperative factors associated with increased in-hospital mortality were preoperative creatinine greater than 1.6 mg/dL (p < 0.001), emergency operation (p < 0.001), female sex (p = 0.012), moderate or severe left ventricular dysfunction (p = 0.049), and left main coronary disease (p = 0.045). In-hospital, actuarial survival was 75% at 5 years and 49% at 10 years. Cardiac event-free survival was 60% at 5 years and 27% at 10 years. The factors independently associated with increased late death were hematocrit (p = 0.046), diabetes (p = 0.011), peripheral vascular disease (p < 0.001), left ventricular function (p < 0.001), history of cancer (p = 0.016), preoperative nonsinus rhythm (p = 0.003), anticoagulation or antiplatelet therapy (p = 0.018), postoperative encephalopathy (p = 0.001), and postoperative stroke (p = 0.014).

CONCLUSIONS

CABG reoperation can have excellent results for many elderly patients, but mortality is markedly higher when elderly patients have certain risk factors and comorbidities, alone or in combination. This information should be helpful in educating patients before they decide whether to choose reoperation.

The Cox-Maze procedure: the Cleveland Clinic experience

The Cox-Maze procedure was designed to address the consequences of atrial fibrillation, tachycardia, hemodynamic impairment, and thromboembolism. From 1991 until June 1999, 100 patients underwent the Maze operation at the Cleveland Clinic Foundation. The group included 72 men with a mean age of 58 +/- 11 years (range, 23 to 78 years). Initially, the Maze-I procedure was performed primarily for patients with lone atrial fibrillation. However, since 1995, the Maze-III procedure has been performed exclusively, and it is typically combined with mitral valve repair. Twenty-three patients had only a Maze procedure, 60 patients had the Maze procedure/mitral valve repair, 10 patients had Maze procedure/coronary artery bypass, 6 had Maze procedure/mitral valve replacement, and 1 had Maze procedure/atrial septal defect repair. Chronic atrial fibrillation was present in 78% of patients for a mean of 8 +/- 9 years. There was a 1% perioperative mortality and 5% late mortality rate. Median hospital stay was 9 +/- 5 days. Six patients required new early permanent pacemaker insertion. With a mean follow-up of 3 years, 90.4% of patients are in sinus rhythm (or atrial pacing). Preoperative symptoms were reduced: 24% had preoperative syncope; none had syncope in follow-up; 14% of patients preoperatively had cerebral or systemic emboli; and there were no perioperative or late embolic events. The Maze procedure effectively addressed the major complications of atrial fibrillation and was associated with low perioperative and late morbidity rates.

Preoperative risk factors for right ventricular failure after implantable left ventricular assist device insertion

BACKGROUND

Implantable left ventricular assist device (LVAD) insertion complicated by early right ventricular (RV) failure has a poor prognosis and is generally unpredictable.

METHODS

To determine preoperative risk factors for perioperative RV failure after LVAD insertion, patient characteristics and preoperative hemodynamics were analyzed in 100 patients with the HeartMate LVAD (Thermo Cardiosystems, Inc, Woburn, MA) at the Cleveland Clinic.

RESULTS

RV assist device support was required for 11 patients (RVAD group). RVAD use was significantly higher in younger patients, female patients, smaller patients, and myocarditis patients. There was no significant difference in the cardiac index, RV ejection fraction, or right atrial pressure between the two groups preoperatively. The preoperative mean pulmonary arterial pressure (PAP) and RV stroke work index (RV SWI) were significantly lower in the RVAD group (p = 0.015 and p = 0.011, respectively). Survival to transplant was poor in the RVAD group (27%) and was 83% in the no-RVAD group.

CONCLUSIONS

The need for perioperative RVAD support was low, only 11%. Preoperative low PAP and low RV SWI were significant risk factors for RVAD use.

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.

Oral steroid pulse without taper for the treatment of asymptomatic moderate cardiac allograft rejection

BACKGROUND

The most frequently administered treatment for asymptomatic ISHLT Grade 3A cardiac allograft rejection is intravenous steroids or oral steroid pulse with a taper. This study analyzes the efficacy of 3-day 100-mg course of prednisone without a tapered regimen for the treatment of asymptomatic moderate cardiac allograft rejection.

METHODS

All new episodes of asymptomatic ISHLT Grade 3A rejections were treated with oral steroid pulse without taper, consisting of 100 mg of prednisone for 3 consecutive days followed by resuming the pre-rejection steroid dose on the fourth day. We retrospectively reviewed the histologic response of all treated episodes among all cardiac transplant recipients transplanted between January 1995 through December 1997 who were treated with triple therapy consisting of cyclosporine, azathioprine and steroids. Patients receiving additional or alternative immunosuppressives were excluded from the study. The treated episodes were analyzed as responders if the follow-up biopsy were Grade 0, 1A, 1B, or 2; treatment was counted as non-responders if the follow-up biopsy showed Grade 3A or higher.

RESULTS

Of 230 cardiac transplant recipients, 100 patients received a 3-day 100 mg course of prednisone without taper for 174 new episodes of asymptomatic ISHLT Grade 3A rejection. The overall response rate was 75% (130/174 rejection episodes). A significant difference in the response rate was observed depending on the number of days post transplant. A comparison of the success rates among rejections which occurred > 90 days post transplant versus < 30 days revealed responses to be 88% versus 70% (p = 0.02); for rejections treated > 60 days post transplant versus < 30 days showed success rates of 84% versus 70% (p = 0.04). The mean age of the recipient revealed a trend to be lower among the non-responder group (49+/-12 years versus 53+/-9 years, p = 0.07). Having left ventricular assist device as a bridge to transplant did not significantly affect the treatment outcome. The response rates were 69% for the patients who required the assist device versus 77% for those not bridged (p = ns). There was no significant difference in the gender or the baseline immunosuppressive doses between the responders and non-responders. The cost of a 3-day outpatient, visiting nurse supervised intravenous steroid therapy versus 3 days of oral prednisone was $861 vs $6.88.

CONCLUSION

Oral steroid pulse without taper is an effective and economical way to treat asymptomatic moderate grade cardiac allograft rejection. A 3-day course of 100 mg of prednisone without taper should be considered as first line of therapy for clinically stable form of moderate cardiac allograft rejection occurring > 60 days post transplant.

Initial clinical experience of real-time three-dimensional echocardiography in patients with ischemic and idiopathic dilated cardiomyopathy

The geometry of the left ventricle in patients with cardiomyopathy is often sub-optimal for 2-dimensional ultrasound when assessing left ventricular (LV) function and localized abnormalities such as a ventricular aneurysm. The aim of this study was to report the initial experience of real-time 3-D echocardiography for evaluating patients with cardiomyopathy. A total of 34 patients were evaluated with the real-time 3D method in the operating room (n = 15) and in the echocardiographic laboratory (n = 19). Thirteen of 28 patients with cardiomyopathy and 6 other subjects with normal LV function were evaluated by both real-time 3-D echocardiography and magnetic resonance imaging (MRI) for obtaining LV volumes and ejection fractions for comparison. There were close relations and agreements for LV volumes (r = 0.98, p <0.0001, mean difference = -15 +/- 81 ml) and ejection fractions (r = 0.97, p <0.0001, mean difference = 0.001 +/- 0.04) between the real-time 3D method and MRI when 3 cardiomyopathy cases with marked LV dilatation (LV end-diastolic volume >450 ml by MRI) were excluded. In these 3 patients, 3D echocardiography significantly underestimated the LV volumes due to difficulties with imaging the entire LV in a 60 degrees x 60 degrees pyramidal volume. The new real-time 3D echocardiography is feasible in patients with cardiomyopathy and may provide a faster and lower cost alternative to MRI for evaluating cardiac function in patients.

Atrial L-type Ca2+ currents and human atrial fibrillation

Chronic atrial fibrillation (AF) is characterized by decreased atrial contractility, shortened action potential duration, and decreased accommodation of action potential duration to changes in activation rate. Studies on experimental animal models of AF implicate a reduction in L-type Ca2+ current (I(Ca)) density in these changes. To evaluate the effect of AF on human I(Ca), we compared I(Ca) in atrial myocytes isolated from 42 patients in normal sinus rhythm at the time of cardiac surgery with that of 11 chronic AF patients. I(Ca) was significantly reduced in the myocytes of patients with chronic AF (mean -3.35+/-0.5 pA/pF versus -9.13+/-1. 0 pA/pF in the controls), with no difference between groups in the voltage dependence of activation or steady-state inactivation. Although I(Ca) was lower in myocytes from the chronic AF patients, their response to maximal beta-adrenergic stimulation was not impaired. Postoperative AF frequently follows cardiac surgery. Half of the patients in the control group (19/38) of this study experienced postoperative AF. Whereas chronic AF is characterized by reduced atrial I(Ca), the patients with the greatest I(Ca) had an increased incidence of postoperative AF, independent of patient age or diagnosis. This observation is consistent with the concept that calcium overload may be an important factor in the initiation of AF. The reduction in functional I(Ca) density in myocytes from the atria of chronic AF patients may thus be an adaptive response to the arrhythmia-induced calcium overload.

Is anterior leaflet repair always necessary in repair of bileaflet mitral valve prolapse?

BACKGROUND

Traditionally, bileaflet prolapse has been treated by posterior leaflet resection combined with one of a number of procedures designed to support the anterior leaflet. However, most patients with bileaflet prolapse do not have important anterior chordal pathology. This study was undertaken to evaluate the effectiveness of a strategy of posterior leaflet resection and annuloplasty alone for patients with bileaflet prolapse and no anterior chordal rupture or severe anterior chordal elongation.

METHODS

From 1993 to 1997, 93 patients with transesophageal echocardiography (TEE) demonstrated bileaflet prolapse and without anterior chordal rupture or important anterior chordal elongation had primary isolated mitral valve repair consisting only of posterior leaflet resection (quadrangular in 28 and sliding in 65) and annuloplasty (Cosgrove-Edwards in 83, pericardial in 9, and Carpentier-Edwards in 1). All patients had severe mitral regurgitation documented by intraoperative TEE. Mean age was 55+/-13 years; 60% were men.

RESULTS

Postrepair, mitral regurgitation was 0 to trace in 93% and 1+ in 7%. There were no operative deaths. Late follow-up was available in all patients, with 277 patient-years of follow-up available for analysis. Five-year actuarial survival was 95%. At a mean interval of 2.3+/-1.3 (SD) years, echocardiography demonstrated no or trace mitral regurgitation in 65%, 1+ in 28%, and 2+ in 7%. No correlates of late mitral regurgitation were identified by multivariable analysis. No patient has required reoperation.

CONCLUSIONS

In the absence of significant anterior chordal pathology, a strategy of posterior leaflet resection and annuloplasty corrects anterior leaflet prolapse and mitral regurgitation, and provides a durable repair without the necessity of additional procedures on the anterior leaflet.

Noninvasive assessment of left atrial maximum dP/dt by a combination of transmitral and pulmonary venous flow

OBJECTIVES

The study assessed whether hemodynamic parameters of left atrial (LA) systolic function could be estimated noninvasively using Doppler echocardiography.

BACKGROUND

Left atrial systolic function is an important aspect of cardiac function. Doppler echocardiography can measure changes in LA volume, but has not been shown to relate to hemodynamic parameters such as the maximal value of the first derivative of the pressure (LA dP/dt(max)).

METHODS

Eighteen patients in sinus rhythm were studied immediately before and after open heart surgery using simultaneous LA pressure measurements and intraoperative transesophageal echocardiography. Left atrial pressure was measured with a micromanometer catheter, and LA dP/dt(max) during atrial contraction was obtained. Transmitral and pulmonary venous flow were recorded by pulsed Doppler echocardiography. Peak velocity, and mean acceleration and deceleration, and the time-velocity integral of each flow during atrial contraction was measured. The initial eight patients served as the study group to derive a multilinear regression equation to estimate LA dP/dt(max) from Doppler parameters, and the latter 10 patients served as the test group to validate the equation. A previously validated numeric model was used to confirm these results.

RESULTS

In the study group, LA dP/dt(max) showed a linear relation with LA pressure before atrial contraction (r = 0.80, p < 0.005), confirming the presence of the Frank-Starling mechanism in the LA. Among transmitral flow parameters, mean acceleration showed the strongest correlation with LA dP/dt(max) (r = 0.78, p < 0.001). Among pulmonary venous flow parameters, no single parameter was sufficient to estimate LA dP/dt(max) with an r2 > 0.30. By stepwise and multiple linear regression analysis, LA dP/dt(max) was best described as follows: LA dP/dt(max) = 0.1 M-AC +/- 1.8 P-V - 4.1; r = 0.88, p < 0.0001, where M-AC is the mean acceleration of transmitral flow and P-V is the peak velocity of pulmonary venous flow during atrial contraction. This equation was tested in the latter 10 patients of the test group. Predicted and measured LA dP/dt(max) correlated well (r = 0.90, p < 0.0001). Numerical simulation verified that this relationship held across a wide range of atrial elastance, ventricular relaxation and systolic function, with LA dP/dt(max) predicted by the above equation with r = 0.94.

CONCLUSIONS

A combination of transmitral and pulmonary venous flow parameters can provide a hemodynamic assessment of LA systolic function.

New surgical options for the failing heart

Heart failure is common in patients aged over 65 years, and is the fourth leading cause of hospitalization in the United States. Treatment of congestive heart failure involves remodeling the cardiac chamber with ventricular dilatation. New approaches to resolve this problem include medical therapies (digoxin, diuretics, ACE inhibitors, beta-blockers and phosphodiesterase inhibitors) to stabilize patients, followed by chamber remodeling. As yet, surgical intervention in advanced heart failure has been contraindicated, but newly evolving strategies show significant promise. It appears possible that patients can receive surgical therapy to improve cardiac function, followed by state-of-the-art medical therapy for congestive heart failure. This combined medical/surgical approach has led to the evolution of a new subspecialty within cardiology that deals with the management of heart failure.

A prospective randomized trial of Duraflo II heparin-coated circuits in cardiac reoperations

BACKGROUND

Heparin-coated circuits in cardiopulmonary bypass have been shown to decrease the systemic inflammatory responses associated with cardiopulmonary bypass. Previous clinical studies on low-risk patients who had coronary artery bypass grafting (CABG) and received full-dose systemic heparin did not have clearly improved clinical outcomes. We hypothesized that the beneficial effects of heparin-coated circuits might be seen in patients who had cardiac reoperations.

METHODS

Three hundred fifty patients who had reoperation with CABG only (58%), or with valve operations (42%) were randomly assigned to receive either a heparin-coated (Duraflo II; study group) or uncoated (control group) circuit. Clinical outcomes were compared and the variables were analyzed using the following three groups: entire populations of study group and control group, subgroup of patients who had CABG reoperation only, and a subgroup who had valve reoperation or combined valve and CABG reoperation.

RESULTS

Preoperative variables were the same in both groups. No difference in clinical outcomes could be demonstrated except that the percentage of patients with major bleeding episodes was significantly lower in the study group (1.2% versus 5.4%, p = 0.035). In the subgroup analysis of patients who had valve reoperations, lower blood transfusion requirements in the intensive care unit (p = 0.013) were found in the study group. When the subgroup of patients who had CABG reoperations was analyzed separately, there was a trend toward less reoperation for bleeding in the study group (0% versus 4.0%, p = 0.058).

CONCLUSIONS

We conclude that the use of heparin-coated circuits was safe and imparted protection from reoperations for bleeding and major bleeding episodes. Material-independent blood activation (eg, blood-air interface and cardiotomy suction) blunted the total effect of the heparin-coated surface.

Two internal thoracic artery grafts are better than one

OBJECTIVE

Does the use of bilateral internal thoracic artery (ITA) grafts provide incremental benefit relative to the use of a single ITA graft?

METHODS

We conducted a retrospective, nonrandomized, long-term (mean follow-up interval of 10 postoperative years) study of patients undergoing elective primary isolated coronary bypass surgery who received either single (8123 patients) or bilateral ITA grafts (2001 patients), with or without additional vein grafts. Multiple statistical methods including propensity score matching, and multivariable parsimonious and nonparsimonious risk factor analyses were used to address the issues of patient selection and heterogeneity.

RESULTS

In-hospital mortality was 0.7% for both the bilateral and single ITA groups. Survival for the bilateral ITA group was 94%, 84%, and 67%, and for the single ITA group 92%, 79%, and 64% at 5, 10, and 15 postoperative years, respectively (P <.001). Death, reoperation, and percutaneous transluminal coronary angioplasty were more frequent for patients undergoing single rather than bilateral ITA grafting, and this observation remained true despite multiple adjustments for patient selection, sampling, and length of follow-up. The differences between the bilateral and single ITA groups were greatest in regard to reoperation. The extent of benefit of bilateral ITA grafting varied according to patient-related variables, but no patient subsets were identified for whom single ITA grafting could be predicted to provide an advantage.

CONCLUSIONS

Patients who received 2 ITA grafts had decreased risks of death, reoperation, and angioplasty.

Cerebral embolism associated with left ventricular assist device support and successful therapy with intraarterial urokinase

A patient with a bioprosthetic aortic valve sustained a cerebral embolism during support with an implantable left ventricular assist device. This was lysed with intraarterial urokinase with complete resolution of the neurological deficit. Subsequently the patient underwent heart transplantation and remains neurologically intact. This case report is the first successful use of thrombolysis for cerebral embolism associated with a mechanical assist device.

Vitamin K reduces bleeding in left ventricular assist device recipients

BACKGROUND

Despite advances in left ventricular assist device (LVAD) design that permit support without anticoagulation, LVAD recipients often suffer profound bleeding complications. This bleeding diathesis may be attributable to pre-operative right-ventricular failure with concomitant hepatic dysfunction. The purpose of this study was to characterize coagulation abnormalities in LVAD recipients and determine the impact of pre-operative vitamin K administration on the incidence of postoperative bleeding.

METHODS

Hemostatic and liver function profiles were obtained in 66 recipients of the Heartmate LVAD; 39 of these patients received perioperative vitamin K.

RESULTS

During LVAD support, hepatic synthetic function improved as evidenced by increases in clotting factors II, V, VII, XI. There was ongoing fibrinolysis with elevation of fibrinopeptide A and D-dimers and diminution of fibrinogen; however, plasminogen levels did not decline suggesting that systemic disseminated intravascular coagulation (DIC) did not occur. Bleeding requiring re-exploration more than 48 hours postimplantation occurred in 9 of 66 patients (13.6%). Prior to implantation, patients that bled had decreased levels of factor II (52.2 +/- 27.1% vs 69.7 +/- 26.6%; p = 0.048) and prolonged prothrombin times (16.5 +/- 2.4 seconds vs 13.8 +/- 3.1 seconds; p = 0.005) compared to patients that did not bleed. Seven of 27 patients (25.9%) not treated with vitamin K bled, while only 2 of 39 (5.1%) patients treated with vitamin K required re-exploration for bleeding (p = 0.026).

CONCLUSIONS

We conclude that: (1) Liver synthetic function improves during LVAD support resulting in increased levels of circulating coagulation factors; (2) ongoing fibrinolysis occurs but likely only represents remodeling of fibrin on the LVAD surface; (3) perioperative vitamin K reduces nonsurgical bleeding in LVAD recipients.

Risk factors for intracranial hemorrhage in adults on extracorporeal membrane oxygenation

OBJECTIVE

Intracranial hemorrhage is a recognized complication in neonates and infants on extracorporeal membrane oxygenator support and various risk factors associated with this have been defined. The prevalence and risk factors associated with intracranial hemorrhage in adults on extracorporeal membrane oxygenator support are unknown and this study was performed to define these factors.

METHODS

A retrospective study of adults supported with extracorporeal membrane oxygenators at a single institution between January 1992 and December 1996 was performed. Age, gender, weight, body surface area, renal function, anticoagulation, coagulation variables, blood flow, arterial pressure, arterial cannulation sites, duration of support, extracranial bleeding, native cardiac function and presence of intracranial microemboli were analyzed to determine the risk factors for intracranial hemorrhage.

RESULTS

Fourteen out of 74 adults on extracorporeal membrane oxygenator support had intracranial hemorrhage (18.9%). An increased risk of intracranial hemorrhage showed a positive correlation with female gender (P = 0.02, odds ratio 6.5), use of heparin (P = 0.05, odds ratio 8.5), creatinine greater than 2.6 mg/ dl (P = 0.009, odds ratio 6.5), need for dialysis (P = 0.03, odds ratio 4.3) and thrombocytopenia (P = 0.007, odds ratio 18.3). Diminishing renal function and the need for dialysis were associated with increasing duration of support. Multivariable logistic regression showed female gender and thrombocytopenia, especially with platelet counts less than 50000 cells/mm3 to be the most important predictors of intracranial hemorrhage. Intracranial hemorrhage was associated with a mortality of 92.3% compared with a mortality of 61% in those without intracranial hemorrhage (P = 0.027).

CONCLUSION

Intracranial hemorrhage is a significant complication in adults on extracorporeal membrane oxygenator support. Judicious management of anticoagulation, prevention of renal failure and aggressive correction of thrombocytopenia may help to lower the risk of intracranial hemorrhage in adults on extracorporeal membrane oxygenator support.

Intra-arterial thrombolysis for perioperative stroke after open heart surgery

Recent major surgery is an exclusion criterion for thrombolysis. Six patients with acute ischemic stroke underwent intra-arterial thrombolysis after recent open heart surgery without clinically significant bleeding complications, although one patient developed a small, asymptomatic cerebellar hemorrhage. Intra-arterial thrombolysis may be an option for patients with cerebral embolism in the perioperative period.

Durability of mitral valve repair for degenerative disease

BACKGROUND

Degenerative mitral valve disease is the most common cause of mitral regurgitation in the United States. Mitral valve repair is applicable in the majority of these patients and has become the procedure of choice.

OBJECTIVE

This study was undertaken to identify factors influencing the durability of mitral valve repair.

PATIENTS AND METHODS

Between 1985 and 1997, 1072 patients underwent primary isolated mitral valve repair for valvular regurgitation caused by degenerative disease. Repair durability was assessed by multivariable risk factor analysis of reoperation. It was supplemented by a search for valve-related risk factors for death before reoperation. Three hospital deaths occurred (0.3%); complete follow-up (4152 patient-years) was available in 1062 of 1069 hospital survivors (99.3%).

RESULTS

At 10 years, freedom from reoperation was 93%. Among 30 patients who required reoperation for late mitral valve dysfunction, the repair failed in 16 (53%) as a result of progressive degenerative disease. Durability of repair was adversely affected by pathologic conditions other than posterior leaflet prolapse, use of chordal shortening, annuloplasty alone, and posterior leaflet resection without annuloplasty. Durability was greatest after quadrangular resection and annuloplasty for posterior leaflet prolapse and was enhanced by the use of intraoperative echocardiography. Death before reoperation was increased in patients having isolated anterior leaflet prolapse or valvular calcification and by use of chordal shortening or annuloplasty alone.

CONCLUSIONS

Repair durability is greatest in patients with isolated posterior leaflet prolapse who have posterior leaflet resection and annuloplasty. Chordal shortening, annuloplasty alone, and leaflet resection without annuloplasty jeopardize late results.

Aortic valve replacement for octogenarians: are small valves bad?

BACKGROUND

As the population ages, more octogenarians become candidates for aortic valve replacement. Many octogenarians, particularly women, have a small aortic annulus and there is uncertainty as to the optimal management of this situation in that age group.

METHOD

To examine this issue, we reviewed 248 octogenarians (mean age, 82.6 +/- 2.3 years; 58% men) who underwent primary isolated aortic valve replacement (n = 99), or aortic valve replacement and coronary revascularization (n = 149), between 1980 and 1995. Nineteen-millimeter valves were used in 26% of the patients.

RESULTS

In-hospital mortality was 8.9%, 5% for aortic valve replacement alone and 11.4% for aortic valve replacement and coronary revascularization. It was 12.5% for the 19-mm size valves compared with 7.7% for the bigger size valves (p = 0.24). Follow-up (mean interval, 4.4 years) demonstrated survival for all patients of 85%, 60%, and 30% and survival free from cardiovascular events of 80%, 45%, and 21% at 1, 5, and 10 postoperative years, respectively. Multivariate analysis identified triple-vessel disease and preoperative congestive heart failure as associated with increased risk for both in-hospital and late mortality (p < 0.05). Valve size did not influence late survival or event-free survival regardless of body surface area.

CONCLUSIONS

The use of small aortic valve prostheses in octogenarians does not adversely affect the incidence of early or late mortality or cardiac events.

Vascular rejection post heart transplantation is associated with positive flow cytometric cross-matching

OBJECTIVE

Use of flow cytometry cross-matching for measurement of donor-specific alloreactivity and monitoring anti-donor antibodies is well established. This study was performed to determine (1) its accuracy as a marker of vascular rejection, (2) its correlation with post-transplant outcome and (3) its ability to monitor highly sensitized patients requiring antibody removal with plasma exchange.

METHODS

Serial serum samples from 99 heart transplant recipients were examined for the presence of anti-donor antibodies of the IgG class that were reactive with T and/or B cryopreserved donor lymphocytes. A sub-group of 20 HLA sensitized patients required plasma exchange to remove the anti-HLA antibodies and were monitored with flow cytometry cross-matching to assess the degree of antibody removal.

RESULTS

Positive T-cell reactions were observed in 26 patients and positive B-cell reactions in 54. Twenty patients had vascular rejection. A significantly larger number of patients with a positive flow cytometry cross-match had vascular rejection (42% versus 12% for T-cell reactions, and 32% versus 7% for B-cell reactions; P = 0.002 each). Of the patients who had vascular rejection, 11 had a positive T-cell reaction (flow cytometry cross-match sensitivity of 55%), and 17 had a positive B-cell reaction (sensitivity of 85%). Of the 79 patients who did not develop vascular rejection, 64 had a negative T-cell reaction (specificity of 81%), and 42 had a negative B-cell reaction (specificity of 53%). The actuarial 2-year survival estimates were significantly higher in patients with negative T-cell reactions (90% versus 75%; P = 0.04), and B-cell reactions (95% versus 78%; P = 0.02). In the highly sensitized subgroup (n = 20) the effectiveness of plasma exchange to decrease anti-HLA antibody reactivity was a strong predictor of outcome. For patients in whom plasma exchange (PE) reduced anti-donor reactivity, 1-year survival was 87% compared to 25% in those whom PE did not reduce the level of antibody binding as assessed with flow cytometry cross-matching (P < 0.0001).

CONCLUSIONS

Flow cytometry cross-matching provides a valuable marker for the detection of vascular rejection after cardiac transplantation. Quantitative measurements may allow evaluation of the efficacy of treatment modalities employed in the management of vascular rejection in an attempt to improve outcome.

Risk factors for death after heart transplantation: does a single-center experience correlate with multicenter registries?

BACKGROUND

Risk factors for death after heart transplantation (Tx) are frequently documented from multicenter registries. Although this information is helpful, it reflects a whole range of experiences and results, and may not translate to a particular center. This study was performed to (1) evaluate pre-Tx factors affecting mortality in a single-center experience, and (2) compare these factors with risk factors obtained from multicenter registry reports.

METHODS

Review of our transplant database between January 1984 and December 1995 identified 405 adults who received a primary heart Tx. Multiple factors were analyzed, including demographics, Tx era, cytomegalovirus status, United Network for Organ Sharing status of recipient, presence of pulmonary hypertension, previous cardiac operations, mechanical ventilation or circulatory support, ischemia time, number of rejection episodes, and preoperative flow cytometry crossmatching.

RESULTS

One- and 5-year survival rates were 87.8% and 73.4%, respectively (Kaplan-Meier). Contrary to multicenter registry reports, our data indicate that reoperative procedures, left ventricular assist device support, increasing donor and recipient age, and ischemia time up to 4.2 hours are not risk factors for death after Tx. Likewise, mode of donor death is not a risk factor affecting outcome. Significant risk factors for mortality identified by multivariate analysis included early transplant era (1984 to 1989; p = 0.002), female donor (p = 0.042), cytomegalovirus-seropositive donor (p = 0.048), high pulmonary vascular resistance (p = 0.018), and intraaortic balloon pump support (p = 0.03). It also identified a positive B-cell flow cytometry crossmatch (p = 0.015) to be a risk factor with univariate analysis.

CONCLUSIONS

Our data identify a group of recipients, reportedly at high risk in multicenter registries, who are not at increased risk of death after Tx. This information supports the growing experience with older donors and recipients and with bridged transplants, and has allowed us to expand our donor pool. These prognostic factors at evaluation allow more liberal selection of patients and donors for transplantation.

Exercise performance and chronotropic response in heart failure patients with implantable left ventricular assist devices

During metabolic stress testing, 9 of 20 patients with left ventricular assist devices exhibited a lag in peak device rate by < or = 85% of peak native heart rate (group I), with peak device rates of 118 +/- 9 beats/min compared with group II, in which peak device rate nearly equaled peak native rates. Peak systolic blood pressure was significantly greater in group II than group I, but there was no significant difference in peak oxygen consumption, anaerobic threshold, or peak flows.

One hundred patients with the HeartMate left ventricular assist device: evolving concepts and technology

BACKGROUND

Implantable left ventricular assist devices are common as a bridge to transplantation but are just reaching their goal as an alternative to transplantation.

METHODS

From December 1991 until December 1996, 97 left ventricular assist devices were implanted as a bridge to transplantation, one as an alternative to transplantation, and two as a bridge to recovery. Included were 64 pneumatic devices and 36 electric devices. Most patients (69%) had ischemic cardiomyopathy and most (53%) had had previous cardiac surgery. Preoperative circulatory support (extracorporeal membrane oxygenation) was used in 25.

RESULTS

Perioperative insertion of a right ventricular assist device was unusual (11%). The mean duration of support with a left ventricular assist device (bridge to transplantation) was 70 +/- 41 days (up to 206 days). Survival to transplantation was 76%. Cause of death included multiple organ failure (n = 13), perioperative stroke (n = 5), device failure (n = 5), and controller disconnect (n = 1). Significant risk factors for death included (1) preoperative need for ventilator or extracorporeal membrane oxygenation, (2) elevated blood urea nitrogen, creatinine, or bilirubin, and (3) low pulmonary artery pressures. Risks after insertion of the left ventricular assist device were reoperation for bleeding, support with a right ventricular assist device, dialysis, or device failure. Catastrophic failure of the device occurred 14 times in 12 patients and was treated by emergency pump exchange in six instances. Only two device-related thromboembolic episodes were detected. Positive blood cultures were found in 59% of patients, driveline infection in 28%, and pump infection in 11%.

CONCLUSIONS

The HeartMate device provided excellent hemodynamic support with low device-related thromboembolic events. Infection and reliability of the device contributed to the high cost of therapy. These areas need to be improved for the left ventricular assist device to attain its goal as a viable alternative to transplantation.

Partial left ventriculectomy and mitral valve repair for end-stage congestive heart failure

OBJECTIVE

Partial left ventriculectomy (PLV), pioneered by Batista, has been proposed as an alternative treatment strategy in patients with refractory congestive heart failure. In order to analyze the midterm outcome of PLV and mitral valve (MV) repair and stratify patients according to risk, we prospectively studied 57 consecutive patients who underwent this procedure at the Cleveland Clinic Foundation (CCF).

METHODS

Patients had a mean age of 53 years and were predominantly males (74%). In 95% the etiology of heart failure was idiopathic dilated cardiomyopathy. All patients had a left ventricular end diastolic diameter of >7cm and were in New York Heart Association (NYHA) functional classes III and IV. A total of 54 patients (95%) were awaiting heart transplantation. Preoperatively, requirements included inotropes in 23 (40%), intraaortic balloon pump counterpulsation in 3 (5.3%), and left ventricular assist device placement (LVAD) in 1 (1.8%). Concomitant procedures included MV repair (55 patients), MV replacement (2), tricuspid valve repair (34 patients), coronary artery bypass graft (CABG) (5), and aortic valve repair or replacement (1 patient each).

RESULTS

Measurements preoperatively and at 3 months demonstrated improvement in left ventricular ejection fraction (14.4 +/- 7.7-23.2 +/- 10.7%, P < 0.001), left ventricular end diastolic volume (254 +/- 85-179 +/- 73 ml, P < 0.001) and left ventricular end diastolic diameter (8.4 +/- 1.1-6.3 +/- 0.9 cm, P < 0.001). Peak oxygen consumption (MVO2) increased from 10.6 +/- 3.9 to 15.3 +/- 4.5 ml/kg per min (P < 0.001). Cardiac index did not change (2.2 l/min per m2), although 40% had been on inotropes preoperatively and none were on inotropes at 3 months. NYHA functional class improved from 3.6 +/- 0.5 preoperatively to 2.2 +/- 0.9 at 3 months (P < 0.001). LVAD support was required as rescue therapy in 11 patients (17%). Actuarial freedom from procedure failure, defined as death or relisting for transplant, was 58% at 1 year. Hospital mortality was 3.5% (n = 2). On follow-up, there were 7 late deaths (including 3 sudden deaths) giving an actuarial survival of 82% at 1 year. Multivariate risk factor analysis revealed that age less than 40 years was associated with failure (P = 0.02).

CONCLUSIONS

Although PLV with MV repair is now a surgical option in the treatment of end-stage congestive heart failure, caution is advised as early failures are unpredictable and mechanical support may be required as rescue therapy. Better risk stratification and patient selection may improve outcome. Further study is required to determine the procedure's exact role in the treatment of congestive heart failure.

Left ventricular diastolic filling with an implantable ventricular assist device: beat to beat variability with overall improvement

OBJECTIVES

We studied the effects of left ventricular (LV) unloading by an implantable ventricular assist device on LV diastolic filling.

BACKGROUND

Although many investigators have reported reliable systemic and peripheral circulatory support with implantable LV assist devices, little is known about their effect on cardiac performance.

METHODS

Peak velocities of early diastolic filling, late diastolic filling, late to early filling ratio, deceleration time of early filling, diastolic filling period and atrial filling fraction were measured by intraoperative transesophageal Doppler echocardiography before and after insertion of an LV assist device in eight patients. A numerical model was developed to simulate this situation.

RESULTS

Before device insertion, all patients showed either a restrictive or a monophasic transmitral flow pattern. After device insertion, transmitral flow showed rapid beat to beat variation in each patient, from abnormal relaxation to restrictive patterns. However, when the average values obtained from 10 consecutive beats were considered, overall filling was significantly normalized from baseline, with early filling velocity falling from 87 +/- 31 to 64 +/- 26 cm/s (p < 0.01) and late filling velocity rising from 8 +/- 11 to 32 +/- 23 cm/s (p < 0.05), resulting in an increase in the late to early filling ratio from 0.13 +/- 0.18 to 0.59 +/- 0.38 (p < 0.01) and a rise in the atrial filling fraction from 8 +/- 10% to 26 +/- 17% (p < 0.01). The deceleration time (from 112 +/- 40 to 160 +/- 44 ms, p < 0.05) and the filling period corrected by the RR interval (from 39 +/- 8% to 54 +/- 10%, p < 0.005) were also significantly prolonged. In the computer model, asynchronous LV assistance produced significant beat to beat variation in filling indexes, but overall a normalization of deceleration time as well as other variables.

CONCLUSIONS

With LV assistance, transmitral flow showed rapidly varying patterns beat by beat in each patient, but overall diastolic filling tended to normalize with an increase of atrial contribution to the filling. Because of the variable nature of the transmitral flow pattern with the assist device, the timing of the device cycle must be considered when inferring diastolic function from transmitral flow pattern.

Left and right atrial transport function after the Maze procedure for atrial fibrillation: an echocardiographic Doppler follow-up study

OBJECTIVES

We evaluated atrial transport function after the Maze procedure in long-term follow-up and compared left and right atrial function in Maze patients with that of healthy age-matched controls using echo Doppler techniques.

BACKGROUND

The Maze procedure is designed to eliminate atrial fibrillation, restore normal sinus rhythm, and preserve atrial contraction. Initial data indicate that atrial transport function is restored in most patients undergoing the Maze procedure. The long-term echo Doppler evaluation of patients after the Maze procedure has not been well described.

METHODS

We performed pulsed-wave Doppler and two-dimensional echocardiographic studies on 31 patients (24 men, mean age 53.8 years) who underwent the Maze procedure and who had a follow-up study greater than 3 months (mean 16.5 months) after the procedure. Measurements included peak left ventricular and right ventricular inflow A-wave velocity, maximum and minimum left atrial and right atrial areas, and fractional area change of the left and right atria. Results were compared with those obtained from 15 age-matched control subjects (11 men, mean age 53.8 years).

RESULTS

Twenty-two patients (71%) had left atrial function shown by the presence of left ventricular inflow A-wave, and 25 patients (81%) had right atrial function shown by the presence of right ventricular inflow A-wave on Doppler echocardiography. The left ventricular inflow A-wave velocity was significantly lower than that of age-matched controls (37.5 +/- 15.5 versus 61.0 +/- 13.9 cm/sec; p < 0.001), whereas the right ventricular inflow A-wave velocity did not significantly differ between patients and control subjects (35.4 +/- 9.9 versus 35.3 +/- 4.9 cm/sec; p = Not significant). Although left and right atrial areas decreased significantly after the procedure, there was no significant change in the fractional area change which was smaller in Maze patients than control individuals.

CONCLUSIONS

(1) In long-term follow-up of 16.5 months after the Maze procedure, left atrial systolic function was preserved in 71% of our patients and right atrial systolic function was preserved in 81%; (2) the left ventricular inflow peak A-wave velocity after Maze is considerably less than that in age-matched controls; and (3) left and right atrial sizes decreased after the procedure with no change in the fractional area change. These findings suggest that the Maze procedure is effective in restoring atrial function in the majority of patients; however, restored function is less than in control individuals.

Early results with partial left ventriculectomy

OBJECTIVE

We sought to determine the role of partial left ventriculectomy in patients with dilated cardiomyopathy.

METHODS

Since May 1996 we have performed partial left ventriculectomy in 53 patients, primarily (94%) in heart transplant candidates. The mean age of the patients was 53 years (range 17 to 72 years); 60% were in class IV and 40% in class III. Preoperatively, 51 patients were thought to have idiopathic dilated cardiomyopathy, one familial cardiomyopathy, and one valvular cardiomyopathy. As our experience accrued we increased the extent of left ventriculectomy and more complex mitral valve repairs. For two patients mitral valve replacement was performed. For 51 patients the anterior and posterior mitral valve leaflets were approximated (Alfieri repair); 47 patients also had ring posterior annuloplasty. In 27 patients (51%) one or both papillary muscles were divided, additional left ventricular wall was resected, and the papillary muscle heads were reimplanted.

RESULTS

Echocardiography showed a significant decrease in left ventricular dimensions after resection (8.3 cm to 5.8 cm), reduction in mitral regurgitation (2.8+ to 0), and increase in forward ejection fraction (15.7% to 32.7%). Cardiac index did not increase significantly (2.2 to 2.4 L/min per square meter). Eight patients (15%) required a perioperative left ventricular assist device; one died and was the only perioperative mortality (1.9%). At 11 months, actuarial survival was 87% and freedom from relisting for transplantation was 72%.

CONCLUSIONS

Improved selection criteria are necessary to avoid early failures, and much more follow-up and analyses of data are mandatory. However, the operation may become a biologic bridge, or even alternative, to transplantation.

Third coronary artery bypass operations: risks and costs

BACKGROUND

Third coronary artery bypass operations are technically difficult and are associated with increased risk.

METHODS

We reviewed the cases of 469 patients who had undergone a third isolated coronary artery bypass operation and used univariate and multivariate testing to examine the effect of preoperative and operative variables on outcome and costs.

RESULTS

The in-hospital mortality was 7.0% (33 patients). Advanced age and severe symptoms were found to increase risk (both p < 0.05): the mortality was 14% (n = 74) in patients 70 years old or older who had severe symptoms. However, the overall mortality for 1993 through 1995 was 4.3% (5/117) and only one death (1.3%) occurred among the 79 patients who were less than 70 years old. The late survival rate was 94%, 84%, and 66% at 1, 5, and 10 postoperative years, respectively, and predictors of decreased late survival were advanced age, abnormal left ventricular function, and diabetes (all p < 0.05). Again, age of 70 years or more was a predictor of a poor outcome. Only 52% of patients in that subgroup (including both early and late mortality) were alive 5 years after operation. Analysis of direct hospital costs showed that the mean costs of third coronary artery bypass operations were 21% higher than the mean costs of primary operations but that the elevation in the mean costs for third operations was related to very high costs in 4 patients. Sex was found to influence the cost of both primary and third operations (increased cost for women).

CONCLUSIONS

Unfavorable outcomes after third coronary artery bypass operations have been associated with preoperatively definable variables, particularly age of 70 years or more. The in-hospital mortality in patients younger than 70 was low, and long-term survival in this group has been favorable. The increased hospital costs associated with third operations are related to high costs in only a few patients and have been unpredictable.

Factors influencing HLA sensitization in implantable LVAD recipients

BACKGROUND

Patients bridged to transplantation (TX) with the implantable left ventricular assist device (LVAD) may be at increased risk for the development of panel-reactive antibodies (PRA) during support.

METHODS

To investigate that, we evaluated 60 patients who received the HeartMate LVAD at our institution, of whom 53 had PRA results available for analysis. T lymphocyte PRA levels were examined before LVAD, at the peak PRA level during LVAD support (PEAK), and just before TX. A PRA level more than 10% was considered indicative of sensitization against HLA antigens.

RESULTS

The only factor that had a significant effect on PRA levels before LVAD was patient's sex (1.3% for men versus 7.4% for women; p = 0.005). During LVAD support, peak PRA levels increased significantly and the sex-associated differences were no longer evident (33.3% men, 34.3% women; not significant). At the time of TX, PRAs decreased to 10.9% (men) and 7.0% (women) (not significant). We examined the influence of blood products received before TX on PRA levels. Patients who received less than the median number of total units (<median) had lower peak PRA values (22.3% versus 49.2%; p = 0.01) and TX PRA values (3.5% versus 22.1%; p = 0.02) than those receiving more than the median (>median). When examined by the type of blood product, only the number of platelet transfusions significantly increased the peak PRA (<median: 24% versus >median: 46.9%; p = 0.03). Patients who received blood that was leukocyte-depleted tended to have lower TX PRA levels (2.9%) compared with those who did not (13.9%, p = 0.18). Forty-two patients were successfully bridged to TX, with three early and two late deaths after TX. Whereas 39 patients received transplants without intervention, 3 were treated by plasmapheresis with a 77% reduction in their HLA antibody levels at TX as measured by flow cytometry.

CONCLUSIONS

Patients with the implantable LVAD are at significant risk for the development of anti-HLA antibodies during support. Although this sensitization is often transient, intervention using plasmapheresis may be useful for some patients.

Aortopulmonary fistula in an infected Dacron graft for coarctation of the aorta: an uncommon cause of hemoptysis

Hemoptysis secondary to an aortobronchial fistula is rare and uniformly fatal when left untreated. The authors describe a case of massive hemoptysis caused by an aortopulmonary fistula in an infected Dacron graft used successfully to repair a coarctation of the aorta.

Extracorporeal life support as a post left ventricular assist device implant supplement

Extracorporeal life support (ECLS) is indicated following left ventricular assist device (LVAD) implant for right heart failure or pulmonary dysfunction. From December 1991 to December 1996, 100 patients were supported with the implantable HeartMate LVAD. Of these, 12 patients were supported with ECLS post LVAD implant. Pre-operatively, 10 patients (83%) were on an intra-aortic balloon pump, 9 patients (75%) were intubated, and 8 patients (67%) required ECLS bridge to LVAD implant. Six patients (50%) were men, and patient age ranged from 28 to 63 years (mean 46 +/- 10 years). Duration of ECLS averaged 3 +/- 2 days (range, 1-9 days). Eight patients (67%) required a right ventricular assist device (RVAD) with an ECLS circuit, three patients (25%) required peripheral veno-venous ECLS, and one patient peripheral veno-arterial ECLS. Forty-five percent supported with ECLS post LVAD survived to transplant compared with the 81% supported with LVAD only. Early in this experience, three patients had RVAD support only and all three patients died. RVAD support (with or without ECLS) was 11% overall and declined from 14% in the first 50 patients to 8% in the second 50. ECLS post LVAD is relatively uncommon and its use is associated with reduced survival, but helps salvage these critically ill patients.

Venovenous extracorporeal life support for patients after cardiotomy

Pulmonary edema and acute lung injury are common sequelae after cardiopulmonary bypass. Increased ventilatory support improves gas exchange, but may compromise ventricular function. From July 1994 to February 1997, nine patients were supported with veno-venous (V-V) extracorporeal life support (ECLS) for post cardiotomy respiratory failure. The mean age was 53 +/- 13 years (range: 37-80 years), and eight (89%) were men. Pre-operatively, five of nine (56%) were intubated, three (33%) were supported with an intra-aortic balloon pump, and five (56%) were on veno-arterial ECLS. Four patients were post left ventricular assist device (LVAD) implantation, one each after resection of an aortic aneurysm, mitral valve replacement and bypass grafting, aortic valve replacement, and pulmonary embolectomy and heart transplantation. Mean duration of support was 2 +/- 1 days (range: 1-4 days). Patients were intubated for a mean of 2 +/- 22 days (range: 4-71 days). One patient (11%) required mediastinal re-exploration secondary to bleeding, two patients underwent hemodialysis or ultrafiltration, and seven (77%) developed bacterial pneumonia. All patients were weaned from ECLS. Six patients (67%) survived to hospital discharge. Cause of death was multiple organ failure in two patients; one died from respiratory failure. V-V ECLS is a useful alternative to open sternotomy for ventilatory induced hemodynamic compromise post cardiotomy, especially in patients with LVADs.

Outward K+ current densities and Kv1.5 expression are reduced in chronic human atrial fibrillation

Chronic atrial fibrillation is associated with a shortening of the atrial action potential duration and atrial refractory period. To test the hypothesis that these changes are mediated by changes in the density of specific atrial K+ currents, we compared the density of K+ currents in left and right atrial myocytes and the density of delayed rectifier K+ channel alpha-subunit proteins (Kv1.5 and Kv2.1) in left and right atrial appendages from patients (n = 28) in normal sinus rhythm with those from patients (n = 15) in chronic atrial fibrillation (AF). Contrary to our expectations, nystatin-perforated patch recordings of whole-cell K+ currents revealed significant reductions in both the inactivating (ITO) and sustained (IKsus) outward K+ current densities in left and right atrial myocytes isolated from patients in chronic AF, relative to the ITO and IKsus densities in myocytes isolated from patients in normal sinus rhythm. Quantitative Western blot analysis revealed that although there was no change in the expression of the Kv2.1 protein, the expression of Kv1.5 protein was reduced by > 50% in both the left and the right atrial appendages of AF patients. The finding that Kv1.5 expression is reduced in parallel with the reduction in delayed rectifier K+ current density is consistent with recent suggestions that Kv1.5 underlies the major component of the delayed rectifier K+ current in human atrial myocytes, the ultrarapid delayed rectifier K+ current, IKur. The unexpected finding of reduced voltage-gated outward K+ current densities in atrial myocytes from AF patients demonstrates the need to further examine the details of the electrophysiological remodeling that occurs during AF to enable more effective and safer therapeutic strategies to be developed.

Permanent mechanical circulatory support with an implantable left ventricular assist device

A 67-year-old man had end-stage ischemic cardiomyopathy. He had had two previous coronary bypass operations and a previous left ventricular aneurysmectomy. In December 1995 he underwent vented-electric HeartMate LVAD insertion as an alternative to transplantation. He was discharged from the hospital 13 days after the operation, and 5 months postoperatively he had returned to New York Heart Association functional class II.

Physical and physiological determinants of pulmonary venous flow: numerical analysis

To study the physical and physiological determinants of transmitral and pulmonary venous flow, a lumped-parameter model of the cardiovascular system has been created, modeling the instantaneous pressure, volume, and influx/efflux of the pulmonary veins, left atrium and ventricle, systemic arteries and veins. right atrium and ventricle, and pulmonary arteries. Initial validation has been obtained by direct comparison with transesophageal echocardiographic recordings of mitral and pulmonary venous velocity for the following clinical situations: normal diastolic function, delayed ventricular relaxation, restrictive filling due to severe systolic dysfunction, severe mitral regurgitation before and after valve repair surgery, and premature atrial contraction occurring during ventricular systole. Sensitivity analysis has been performed with a Jacobian matrix, representing the proportional change in a group of output indexes (yi) in response to isolated changes in input parameters (xj), [(delta yi/yi)/ ([delta xj/xj)], demonstrating the complementary nature of mitral and pulmonary venous A-wave velocity for predicting ventricular stiffness and atrial systolic function. This unified numerical-experimental programming environment should facilitate model refinement and physiological data exploration, in particular guiding more accurate interpretations of Doppler echocardiographic data.

Will permanent LVADs be better than heart transplantation?

Current interest in permanent mechanical support systems has been renewed as a result of the present shortage of human heart donors, and in view of the satisfactory results obtained with their use as a bridge-to-transplant. As the number of donors is unlikely to increase dramatically in the near future, there is an urgent need to develop mechanical alternatives to transplantation. Preliminary data on the use of the implantable electric LVAD as a bridge-to-transplant indicate that the adverse clinical and mechanical events in outpatients are few and do not preclude use of the device on a permanent basis. Except for infections, transplant issues relating to need for endomyocardial biopsies, rejection, malignancies, and graft arteriosclerosis do not apply to LVAD recipients who face important issues relating to device durability, cost, and potential need for concomitant right heart support. This lack of data on long-term durability contrasts with a yearly mortality rate of about 5% after the first year of transplant. With the initiation of clinical trials on the permanent use of the electric LVAD, several design modifications and upgrading of the currently available devices are expected. Completely sealed systems with steadily improving durability will hopefully appear. Inductive coupling techniques under investigation and development appear to be able to transmit energy without damage across the skin. It is anticipated that with more reliable electronic microprocessors, the future generation of implantable LVADs will be smaller, more reliable and longer lasting.

Reoperation for failure of mitral valve repair

BACKGROUND AND OBJECTIVE

Mitral valve repair is the procedure of choice to correct mitral regurgitation of all types. Up to 10% of patients who undergo mitral valvuloplasty require late reoperation for recurrent mitral valve dysfunction. To determine the causes of failed mitral valve repair, we examined the surgical pathology of patients who underwent reoperation for failed mitral valve repair.

PATIENTS AND RESULTS

From 1986 to 1994, 81 patients had 86 reoperations for recurrent mitral regurgitation after mitral valve repair. Mean age was 59.2 +/- 1.4 years; 55 were men. Primary valve disease was degenerative in 48 patients (59%), rheumatic in 16 (20%), ischemic in 13 (16%), endocarditic in 3 (4%), and congenital in 1 (1%). Mean time interval between initial mitral valve repair and reoperation was 15.6 +/- 2.5 months. Causes of repair failure were procedure-related (50 cases, 58%), valve-related (33 cases, 38%), or unknown (3 cases, 3%). Procedure-related valve failure was caused by suture dehiscence (21 cases), rupture of previously shortened chordae (19 cases), or incomplete initial correction (10 cases). Valve-related repair failure was caused by progressive primary valve disease (27 cases), endocarditis (5 cases), or extensive leaflet retraction (1 case). Repair failure was procedure-related in 70% of patients with degenerative valvular disease versus only 13% of patients with rheumatic valvular disease (p = 0.0001). At reoperation, mitral valve replacement was performed in 64 patients (79%) and repeat mitral valve repair in 17 (21%).

CONCLUSION

We conclude that (1) most mitral valve repair failures are procedure-related in degenerative disease and valve-related in rheumatic disease; (2) rupture of previously shortened chordae is a common cause of late failure in patients with degenerative mitral valve disease; and (3) repeat mitral valve repair results in successful treatment for a minority of patients.

Noninvasive assessment of the ventricular relaxation time constant (tau) in humans by Doppler echocardiography

BACKGROUND

The time constant of ventricular relaxation (tau) is a quantitative measure of diastolic performance requiring intraventricular pressure recording. This study validates in humans an equation relating tau to left ventricular pressure at peak -dP/dt (P0), pressure at mitral valve opening (PMV), and isovolumic relaxation time (IVRTinv). The clinically obtainable parameters peak systolic blood pressure (Ps), mean left atrial pressure (PLA), and Doppler-derived IVRT (IVRTDopp) are then substituted into this equation to obtain tau Dopp noninvasively.

METHODS AND RESULTS

High-fidelity left atrial and left ventricular pressure recordings with simultaneous Doppler by transesophageal echocardiography were obtained from 11 patients during cardiac surgery. Direct curve fitting to the left ventricular pressure trace by Levenberg-Marquardt regression assuming a zero asymptote generated tau LM, the "gold standard" against which tau calc (IVRT inv/[ln(P0)-ln(PMV)]) and tau Dopp [IVRTDopp/[ln(Ps)-ln(PLA)]] were compared. For 123 cycles analyzed in 18 hemodynamic states, mean tau LM was 53.8 +/- 12.9 ms. tau calc (51.5 +/- 11 ms) correlated closely with this standard (r = .87, SEE = 5.5 ms). Noninvasive tau Dopp (43.8 +/- 11 ms) underestimated tau LM but exhibited close linear correlation (n = 88, r = .75, SEE = 7.5 ms). Substituting PLA = 10 mm Hg into the equation yielded tau 10 (48.7 +/- 15 ms), which also closely correlated with the standard (r = .62, SEE = 11.6 ms).

CONCLUSIONS

The previously obtained analytical expression relating IVRT, invasive pressures, and tau is valid in humans. Furthermore, a more clinically obtainable, noninvasive method of obtaining tau also closely predicts this important measure of diastolic function.

Experimental and numerically modeled effects of altered loading conditions on pulmonary venous flow and left atrial pressure in patients with mitral regurgitation

Pulmonary venous flow measured by pulsed-wave Doppler transesophageal echocardiography reflects the effects of mitral regurgitation on left atrial pressure contour. To assess the relationship between pulmonary venous flow and left atrial pressure in patients with mitral regurgitation under altered loading conditions, we studied 25 patients with 3+ or 4+ mitral regurgitation and a control group by measuring pulmonary venous flow with transesophageal echocardiography and left atrial pressures after administering saline solution (n = 6), nitroglycerin (n = 6), phenylephrine (n = 6), or nitroprusside (n = 7). After administration, the left atrial pressure v wave increased in the group given phenylephrine, concomitant with an increased diastolic flow. In contrast, the left atrial pressure v wave decreased in the group given nitroglycerin, concomitant with a decreased diastolic flow. Changes in diastolic flow were closely related to changes in the left atrial pressure v wave under all loading conditions (r = 0.91; p < 0.0001). Numeric modeling of left atrial pressure and pulmonary venous diastolic flow corroborated the experimental findings. We conclude that changes in pulmonary venous diastolic flow are closely related to changes in the left atrial pressure v wave in mitral regurgitation, under altered loading conditions.

Does successful bridging with the implantable left ventricular assist device affect cardiac transplantation outcome?

OBJECTIVES

We sought to determine whether cardiac transplant recipients who required a bridge to transplantation with an implantable left ventricular assist device had a different outcome than patients who underwent transplantation without such a bridge.

METHODS

A retrospective study of 256 cardiac transplants from 1992 to 1996 included 53 patients who received the HeartMate left ventricular assist device and 203 patients who had no left ventricular assist device support.

RESULTS

Left ventricular assist device transplants increased from 8% of all transplants in 1992 (n = 63) to 32% in 1995 (n = 65) and 43% in 1996 (n = 14 year to date). Patients with and without left ventricular assist device had similar age and sex distributions. Left ventricular assist device recipients were larger (body surface area 1.96 vs 1.86 m2, p = 0.004). They were more likely to have ischemic cardiomyopathy (70% vs 45%, p = 0.001) and type O blood group (51% vs 34%, p = 0.06). All patients with left ventricular assist device and 42% of those without had undergone previous cardiac operations by the time of transplantation (mean number per patient 1.5 vs 0.3, p < 0.001). More patients in the left ventricular assist device group had anti-HLA antibodies before transplantation (T-cell panel reactive antibody level > 10% in 66% of left ventricular assist device group vs 15% of control group, p < 0.0001). Waiting time was longer for the left ventricular assist device than for patients in status I without a left ventricular assist device (median 88 vs 37 days, p = 0.002). There was no difference in length of posttransplantation hospital stay (median 15 days for each) or operative mortality (3.8% vs 4.4%). Mean follow-up averaged 22 months. No significant difference was found in Kaplan-Meier survival estimates. One-year survival was 94% in the left ventricular assist device group and 88% in the control group (difference not significant). Comparison of posttransplantation events showed no significant difference in actuarial rates of cytomegalovirus infection (20% vs 17%) or vascular rejection (15% vs 12%) at 1 year of follow-up. Similar percentages of patients were free from cellular rejection at 1 year of follow-up (12% vs 22%, p = 0.36).

CONCLUSIONS

Left ventricular assist device support intensified the donor shortage by including recipients who otherwise would not have survived to transplantation. Bridging affected transplant demographics, favoring patients who are larger, have ischemic cardiomyopathy, have had multiple blood transfusions and complex cardiac operations, and are HLA sensitized. Successfully bridged patients wait longer for a transplant than do UNOS status I patients without such a bridge, but they have similar posttransplantation hospital stay, operative mortality, and survival to those of patients not requiring left ventricular assist device support.