Biomedical subjects
Publications and source records attributed to O H Frazier.
We report a case of congenital absence of the anterior pericardium in a 41-year-old man who was undergoing implantation of a left ventricular assist device for treatment of congestive heart failure.
Malignant tumors that metastasize to the heart pose a formidable therapeutic challenge. Recent advances in surgical treatment have improved the management and prognosis of patients with cardiac metastases. We report the case of a 45-year-old man who had a high-grade pleomorphic sarcoma of the right ventricle. We completely resected the neoplasm, reconstructed the right ventricle, and replaced the mitral valve. Upon late follow-up, 67 months (5.6 years) later, the patient was alive and well. This case shows that aggressive surgical management of malignant disease metastatic to the heart can enable prolonged survival.
BACKGROUND AND AIM OF THE STUDY: The hemodynamic characteristics of a new trileaflet mechanical heart valve (TTV) (TriFlo Inc., Costa Mesa, CA, USA) in the aortic position were evaluated in a bovine model. The TTV was designed to combine the durability of mechanical heart valves with the central flow characteristics of a bioprosthesis. METHODS: Using nine calves, the native aortic valve was replaced with a 21-mm TTV (n = 6) or a St. Jude Medical (SJM) valve (n = 3). Hemodynamic values were assessed with echocardiography at implantation and with catheterization at explantation. All calves underwent a necropsy, followed by gross pathology and light microscopy studies. RESULTS: The mean implant duration was 159 +/- 55 days for the TTV and 102 +/- 67 days for the SJM valve. Immediately before euthanasia, the peak and mean pressure gradients were respectively 35 +/- 14 and 24 +/- 9 mmHg for the TTV, and 100 +/- 72 and 59 +/- 38 mmHg for the SJM valve (p = 0.03). Two of the SJM-valve animals were electively sacrificed after showing symptoms of aortic stenosis. At necropsy, all nine valves were free from thrombi, pannus, occlusive tissue, or mechanical impairment of leaflet motion. The prematurely sacrificed SJM-valve animals had concentric myocardial hypertrophy consistent with severe functional aortic stenosis. CONCLUSION: The significantly higher gradients and left ventricular hypertrophy in the SJM-valve animals were related to a smaller effective orifice area, which precluded adaptation to increasing transvalvular volumes in the growing animal. This problem was not seen with the TTV, which performed hemodynamically as well as the SJM valve. The high transvalvular gradients seen with the SJM valve at study end may suggest that the hemodynamic characteristics of the TTV may be superior, though additional studies are needed to confirm this.
Axial flow ventricular assist devices show great promise as a potential treatment for patients with end-stage heart failure. The HeartMate II system, redesigned on the basis of initial clinical experiences in Europe, is now in clinical trials in the United States. We report on the 1st use of the newly redesigned HeartMate II in the United States. The system has unique features, which include an accurate flow estimator and the ability to automatically detect and correct excessive left ventricular unloading. The new design also incorporates changes in the texturing of the blood-contacting surfaces to prevent thrombosis. The implantation technique and configuration are similar to those of the HeartMate XVE LVAS and require a median sternotomy for access. The 1st patient to receive the device in the United States has had an uncomplicated perioperative course and now awaits transplantation.
We evaluated transmyocardial laser revascularization (TMLR) with coronary artery bypass grafting (CABG) versus CABG alone for severe coronary artery disease involving 21 myocardial region unsuited for CABG. At 4 centers, 44 consecutive patients were randomized for CABG+TMLR (n = 23) or CABG alone (n = 21). Operative and in-hospital mortality and morbidity rates were monitored. Clinical status was evaluated at hospital discharge, 1 year, and 4 years. Success was characterized by relief of angina and freedom from repeat revascularization and death. Preoperatively, 20 patients (47%) were at high risk. The CABG technique, number of grafts, and target vessels were similar in both groups. Patients undergoing CABG+TMLR received 25 +/- 11 laser channels. Their < or = 30-day mortality was 13% (3/23) compared with 28% (6/21) after CABG alone (P = 0.21). There were no significant intergroup differences in the number of intraoperative or in-hospital adverse events. The follow-up period was 50.3 +/- 17.8 months for CABG alone and 48.1 +/- 16.8 months for CABG+TMLR. Both groups had substantially improved angina and functional status at 1 and 4 years, with no significant differences in cumulative 4-year mortality. The incidence of repeat revascularization was 24% after CABG alone versus none after CABG+TMLR (P < 0.05). The 4-year event-free survival rate was 14% versus 39%, respectively (P < 0.064). In conclusion, CABG+TMLR appears safe and poses no additional threat for high-risk patients. Improved overall success and repeat revascularization rates may be due to better perfusion of ischemic areas not amenable to bypass. Further studies are warranted to determine whether these trends are indeed significant.
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In this report, we describe successful implantation of a Jarvik 2000 left ventricular assist device (Jarvik Heart, Inc, New York, NY) without the use of cardiopulmonary bypass in a patient who was a member of the Jehovah's Witness faith. To accomplish this, we had to change our implantation technique. The modified technique, which minimizes the risk of bleeding and end-organ dysfunction, can also be used to decrease cardiopulmonary bypass time.
Reports of cardiac transplantation after successful cardiomyoplasty are rare. We report the case of a 63-year-old man with intractable heart failure who underwent successful orthotopic cardiac transplantation 30 months after dynamic cardiomyoplasty.
The AbioCor implantable replacement heart (IRH) is the first available totally implantable artificial heart. We recently initiated a multicenter trial of this device in patients with severe, irreversible biventricular failure. Patients who were not candidates for other therapies, including transplantation, were evaluated. All candidates were adults with inotrope-dependent biventricular failure, whose 30-day predicted mortality was higher than 70%. A three-dimensional computerized fit study predicted fit of the AbioCor thoracic unit in all recipients. At operation, the internal battery controller and transcutaneous energy transfer unit were placed. The AbioCor thoracic unit was placed in an orthotopic position after incision of the ventricals. There were 2 intraoperative deaths (due to intraoperative bleeding or aprotinin reaction). Four late deaths were recorded, 1 from multisystem organ failure and 3 cerebrovascular accidents. Autopsy revealed thrombus on the atrial struts of the 3 patients with cerebrovascular accident. Blood pumps and valves were clean on all patients. Significant morbidity was observed, primarily related to preexisting severity of illness. However, 3 patients recovered to the point of being able to take multiple trips outside of the hospital. Two patients were discharged from the hospital, with 1 patient being discharged home for more than 7 months. No significant device malfunctions or multi-system organ failure device-related infections were noted. The AbioCor IRH may be effective therapy for patients with end-stage heart failure. Many milestones have been achieved in the initial trial in humans, including the successful discharge of a patient to home and no significant device malfunctions. The occurrence of stroke is likely related to the presence of thrombus on the atrial struts and may be decreased as these atrial struts have been removed for future clinical implants.
The donor shortage makes cardiac transplantation a less than ideal treatment for end-stage heart failure. The utility of the left ventricular assist device (LVAD) as a permanent form of circulatory support has recently been established in the REMATCH (Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure) trial. In this report, we describe the surgical management of LVAD patients in REMATCH and their short-term outcomes. Between 1998 and 2001, 129 patients with end-stage heart failure, who were excluded from consideration for transplantation, were enrolled in the REMATCH clinical trial. Patients were randomized to two treatment arms: optimal medical management or HeartMate vented electric LVAD implantation. The primary end point of the study was death from any cause. Secondary end points included the incidence of serious adverse events, the duration of hospitalization, quality of life, and functional status. Sixty-eight patients received an LVAD, 55 (81%) of whom survived for longer than 1 month. The median intensive care unit and hospital lengths of stay (LOS) for those that survived at least 1 month were 15 and 34 days, respectively. Sixty-seven (99%) patients had a serious adverse event. The rates of perioperative bleeding, late bleeding, right heart failure, and sepsis were 0.42, 0.53, 0.15, and 0.53 events/patient-year, respectively. Factors predictive of a longer LOS for the implant hospitalization included sepsis, age, and late bleeding (p < 0.0001). The patients' New York Heart Association functional class improved significantly at 1 month compared with base line (p < 0.001). Functional class improved in LVAD-supported patients despite a high adverse event rate. Most adverse events occurred within 30 days of device implantation. Sepsis, age, and late bleeding were the major determinants of LOS.
Feasibility studies are underway for new axial flow ventricular assist systems and with a total artificial heart (TAH). The axial flow pumps provide continuous flow from the left ventricle (LV) to the aorta; the TAH provides pulsatile flow to the pulmonary and systemic circulation. Understanding the differences between these systems is necessary for appropriate patient selection and management. We compared the Jarvik 2000 axial-flow pump and the AbioCor TAH. The Jarvik 2000 pump is placed in the LV with its outflow graft anastomosed to the aorta. This system is used for bridge-to-transplantation and destination therapy. The AbioCor TAH provides complete circulatory support. The AbioCor is used for destination therapy in patients expected to die in less than 30 days. Worldwide, 45 patients have received the Jarvik 2000 as a bridge to transplantation (n = 34) or destination therapy (n = 11) for an average duration of support of 132.8 days (5 to 853 days). In 30 bridge-to-transplantation cases, 14 patients (47%) have undergone heart transplantation, 5 (17%) continue to be supported with the Jarvik 2000 device, and 11 (37%) have died. Five of 7 patients supported by the AbioCor TAH survived beyond the perioperative period; 4 were ambulatory, 2 were discharged from the hospital, and 1 is at home 13 months after implantation. Anticoagulation therapy and infection management are necessary for both systems. Therapy with inotropic agents, vasoactive drugs, a pacemaker, and electrolyte normalization is necessary for Jarvik patients. AbioCor-supported patients do not require medications to support heart function. Vasoactive agents may be useful for controlling blood pressure.
BACKGROUND: The Jarvik 2000 axial flow left ventricular assist device (LVAD), under development for the past decade, has the potential to support patients temporarily until cardiac transplantation or as a permanent circulatory support, without the size limitations of other implantable systems. METHODS: To assess its ability to perfuse the kidneys and liver, we monitored renal and hepatic function in 10 patients who received the Jarvik 2000 LVAD as a bridge to transplantation. Left ventricular assistance was maintained for up to 214 days (> 6 months), and renal and hepatic function were monitored at least weekly. RESULTS: Renal function before LVAD implantation in these patients was normal in 7 (creatinine, < 1.5) and moderately impaired in 3 (creatinine, 1.2 to 2.0). Hepatic function was normal in 7 patients before LVAD implantation (total bilirubin< 1.2; serum glutamic-oxaloacetic transaminase (SGOT), < 40; serum glutamic-pyruvic transaminase (SGPT), < 50) and normal at the time of transplantation in all 10 patients. Of the 3 patients with abnormal hepatic function before LVAD implantation, 1 patient had also had moderate renal dysfunction. CONCLUSIONS: Despite reduced pulsatility, the Jarvik 2000 LVAD improves or maintains excellent renal and hepatic function during periods of circulatory assistance in patients awaiting transplantation.
In the 1960s, when LVADs and TAHs were introduced into clinical use, researchers estimated that, with this technology, the problem of heart failure could be solved within 20 years. Unfortunately, the evolution of these devices has taken much longer than anticipated. Nevertheless, significant advances have been achieved in both cardiac assistance and replacement, and today's cardiac surgeons have a wide range of devices from which to choose (Table 4). This progress has largely been due to the support of the NHLBI, especially the Devices and Technology Division headed by John Watson, and of the devoted commitment of the investigators. Because of the long-term commitment required for both basic and clinical research, commercial medical technology companies are unable to assume this burden. Advances in mechanical circulatory support and replacement have benefited numerous patients worldwide who would otherwise have died of heart failure, and devices now exist for use as bridges to recovery, bridges to transplant, and destination therapy. The current challenge is to refine what we have and to apply these technologies to broader patient populations with maximal safety and at a reasonable cost.
OBJECTIVES: Low left ventricular ejection fraction (EF) after heart transplantation (HT) is considered an ominous sign. We reviewed our database in order to determine outcomes in patients with low EF after HT and to identify a subset of patients who would benefit from immediate retransplantation. METHODS: We identified 825 patients who underwent HT at our institution between December 1983 and July 1999. Of these, 81 patients (70 men, 11 women; age, 48+/-12 years) had low (<35%) EF as determined by radionuclide ventriculography. Post-transplantation survival; duration of low-EF episodes (>2 years vs. <2 years); and incidence of transplant rejection, infection, and transplant coronary artery disease (CAD) were determined for these patients. RESULTS: On average, low EF developed 800+/-1029 days after HT and lasted 550+/-756 days until improvement, repeat HT, or death of the patient. Actuarial survival was 79% at 1 year, 55% at 3 years, and 46% at 5 years. Shorter (<2-year) episodes of low EF tended to have an earlier onset than prolonged (>2-year) episodes (656 days vs. 1341 days) (P=0.014). Patients with prolonged episodes (n=17) survived longer than patients with shorter episodes (n=64) (2247 days vs. 1266 days) (P=0.002). The incidence of hemodynamically significant rejection was lower in the prolonged low-EF group (6% [1/17] vs. 26% [17/64]) (P=0.03). The incidence of infection (31% vs. 53%) and incidence of transplant CAD (47% vs. 39%) did not differ significantly between the prolonged and shorter low-EF groups. CONCLUSIONS: Low EF after HT, especially with later onset, is not associated with poor survival and is not related to hemodynamically significant rejection. These data further indicate that the presence of low EF even in the setting of CAD is not by itself an indication for repeat HT.
BACKGROUND: Cardiac function may improve in patients with end-stage heart failure who receive long-term support (>30 days) with left ventricular assist devices (LVADs). Dobutamine stress echocardiography (DSE) has been used to quantitate myocardial recovery in patients with heart failure supported with LVADs. By recording the hemodynamic response with the use of DSE, we evaluated and applied the resulting data to patients receiving LVAD support. METHODS AND RESULTS: The study population included 16 patients who underwent LVAD implantation, regained functional capacity on full LVAD support, and tolerated decreased mechanical support with no worsening of dyspnea or fatigue. All 16 patients underwent dobutamine stress with increasing doses of dobutamine (from 5 to 40 mcg/kg/min). Hemodynamics and 2-dimensional (2-D) echocardiography was performed at each dose level. In addition, paired myocardial samples were obtained and analyzed histologically to determine myocyte size and collagen content. Dobutamine stress separated the study population into 2 groups: those who had favorable responses to dobutamine (9/16) and those who had unfavorable responses (i.e., experienced hemodynamic deterioration; 7/16). Favorable dobutamine responses were characterized by improved cardiac index, improved force-frequency relationship in the left ventricle (dP/dt), improved left ventricular ejection fraction, and decreased left ventricular end-diastolic dimension. All 9 favorable responders underwent LVAD explantation, and 6 survived for more than 12 months. In all patients studied, LVAD support resulted in decreased myocyte size (n = 14, 33.9 +/- 0.9 microm before vs 16.6 +/- 0.8 microm after support, p = 0.0001; normal, 5-15 microm) but resulted in no consistent changes in collagen content. CONCLUSIONS: Dobutamine stress echocardiography with hemodynamic assessment may be a useful tool in assessing physiologic improvement in myocardial function of patients with end-stage heart failure who receive LVAD support. It may help predict which patients can tolerate LVAD removal. Prospective analysis of cardiac function is now warranted to better define myocardial recovery in patients supported with LVADs.
BACKGROUND: Left ventricular assist devices (LVADs) currently are used as bridges for patients who deteriorate clinically while awaiting cardiac transplantation. At the time of transplantation or subsequent death, we can assess the effect of long-term device implantation on cardiac structural changes. We have noted, in our years of experience, that aortic valve commissures may fuse in patients supported by LVADs. These observations may be important in the use of these pumps as long-term destination therapy. METHODS: We examined 33 hearts (both explants and autopsy specimens) from patients supported either with vented-electric (VE) HeartMates (n = 21) or with implantable pneumatic HeartMates (n = 12). We noted commissures involved, fusion length (mm), duration of LVAD support, and type of LVAD. As controls, we examined 49 explanted hearts from patients with heart failure who were not supported by LVADs. RESULTS: We found commissural fusion in 17 of the 33 hearts. Of those 17 hearts, 4 (23.5%) had 2 commissural fusions, and 13 (76.5%) had only 1 fusion. Fusion length ranged from 5 mm to 17 mm (mean, 9.9 mm). The lesion was more common in patients fitted with VE HeartMates (p < 0.0002). We found small amounts of commissural fusion in 8 of the 49 control hearts. CONCLUSIONS: Acquired commissural fusion is common in patients supported by LVADs, particularly the VE HeartMate. The lesion also occurs occasionally in failing hearts of patients not supported by LVADs. The significance of the lesion in patients who require long-term LVAD support either as a bridge to transplantation or as destination therapy is unclear.