Biomedical subjects
Publications and source records attributed to R M Adamson.
Tissue adhesives have been available and in use for more than 40 years. They have, however, never been popular for ossiculoplasty because of the reported excessive inflammatory reaction and ototoxicity. The authors present a case of ossicular disruption successfully repaired with tissue adhesive and review the literature.
Implantation of left ventricular assist systems (LVASs) is becoming more prevalent for patients with end-stage heart disease who are awaiting cardiac transplantation. The original intent of the LVAS was to provide an alternative to transplantation, but until recently, the LVAS has been approved only as a bridge to transplantation. Now that bridging to transplantation for patients with LVASs has exceeded 2-year periods, permanent implantation is being done as an alternative to transplantation. This article reviews the fundamental components of the HeartMate Vented Electric LVAS (Thermo Cardiosystems, Inc, Woburn, MA) with a focus on patient complications and nursing implications. Additionally, the intraoperative implantation procedure is presented. Finally, ethical and financial considerations related to permanent LVAS implantation are discussed.
The purpose of this study, was to ascertain whether delayed sternal closure (DSC) could eliminate the need for an intra-aortic balloon pump (IABP) or ventricular assist device (VAD) in patients with low cardiac output syndrome (LCOS) following coronary artery bypass grafting surgery (CABG). To investigate this, the records of 3014 patients undergoing CABG were retrospectively reviewed. Sixty (2.0%) patients had a relative or absolute contraindication to IABP or VAD use and required DSC for LCOS. DSC resolved 45 (75%) of these patients' LCOS, requiring an average of 1.6 +/- 0.7 days and producing a mean change in cardiac index of +1.0 +/- 0.3 L/min/m2. Fifteen (25%) of these patients did not resolve their LCOS after DSC and required either an IABP (11) or a VAD (4). Significant postoperative morbidity occurred in 22 (36.7%) patients but were not related to DSC. Only one (1.7%) sternal wound infection occurred from a total of 147 patient-days of DSC. Operative mortality was 47 per cent (28) but was not unexpected based on the number of urgent/emergent (48; 80%) and reoperative (40; 67%) procedures but does not appear to be related to the technique of DSC. DSC appears to be a simple and safe method for treating LCOS following CABG. It is effective in resolving the majority of patients' LCOS without the addition of any significant morbidity. DSC also spares these patients the added morbidity, mortality, and cost associated with circulatory assist devices.
BACKGROUND: Myocardial hypothermia of less than 10 degrees C is an essential component of preservation of donor hearts before implantation. Here we report temperature changes and comparison of methods for maintenance of myocardial hypothermia during implantation. METHODS: Twenty patients were prospectively randomized into two equal groups. In one cohort myocardial hypothermia was maintained by the "Stanford method" of continuous lavage of the pericardium and left atrium with refrigerated saline solution. In the other a cooling jacket was used without saline lavage. Temperatures at multiple sites were measured at 30-second intervals from initiation of cardiac suturing until aortic cross-clamp removal. Comparisons were made between groups at each temperature site. RESULTS: The cooling jacket group temperatures were significantly lower at the left ventricular epicardium and endocardium than those of the Stanford method group. CONCLUSIONS: During cardiac implantation maintenance of myocardial hypothermia with a cooling jacket resulted in significantly deeper and more consistent hypothermia of the left ventricle than pericardial and left atrial lavage with refrigerated saline solution. Blood loss from aspirated saline lavage and perfusate dilution by the saline solution were eliminated.
A significant cost reduction is likely if patients who require coronary artery bypass grafting with significant carotid stenosis have simultaneous carotid endarterectomy and bypass grafting, provided risk is not increased. To investigate this issue, we retrospectively identified cases from February 1977 to May 1994 with first-time isolated carotid endarterectomy, coronary bypass, or combined procedures. In the isolated carotid endarterectomy population, median age was 69 years and 58% (85/146) were male, as compared with 68 years and 68% (68/100) male in the combined group; median age of the coronary bypass cohort was 65 years and 76% (381/500) male. A significantly higher percentage of patients in the coronary bypass versus combined group were in New York Heart Association functional class IV. In the combined group there was a significantly higher incidence of older age, diabetes, hypertension, hyperlipidemia, renal failure, and congestive heart failure. There was no difference among the three groups with respect to hospital mortality (0%, 3.4%, and 4.0%, respectively) and permanent stroke (0.7%, 1.2%, and 0%, respectively). Hospital costs were $4,896, $10,959 and $11,089, respectively, with a savings of $4,766 (30%), and Medicare hospital reimbursement was $8,575, $23,071, and $23,071, respectively, with a savings of $10,077 (25.3%). Thus, in appropriate patients, a combined procedure is cost effective, eliminating a second surgical procedure and the cost of the postoperative stay (3.7 +/- 2.4 days) associated with isolated carotid endarterectomy. Risk of permanent stroke or death is not increased.
A new technique using the Thompson self-retaining retractor system (Thompson Surgical Instruments, Inc, Traverse City, MI) to harvest lesser saphenous veins is presented. This modification, used in 10 patients undergoing redo myocardial revascularization, provided a rapid, comfortable, and convenient method for harvesting lesser saphenous veins.
The prophylactic use of aprotinin has recently been reported to be associated with a significant decrease in blood loss in patients undergoing cardiopulmonary bypass procedures. One of the primary effects of aprotinin is prevention of plasmin degradation of platelet function. Because aprotinin is commercially unavailable in the United States at this time, we evaluated epsilon-aminocaproic acid with respect to decreased perioperative blood loss. We prospectively randomized 40 patients undergoing first-time coronary artery bypass grafting without prior sternotomy into two groups: one group (n = 21) received prophylactic and preincision epsilon-aminocaproic acid and the other (n = 19) received a placebo. No significant differences existed between patient groups with respect to age, body surface area, cardiopulmonary bypass time, and aortic crossclamp time. Cumulative blood loss at 4, 8, 12, and 24 hours after chest closure was significantly less in the epsilon-aminocaproic acid group (426 +/- 242 ml versus 634 +/- 224 ml, p = 0.002, at 12 hours). Only one patient receiving epsilon-aminocaproic acid was given blood or blood components compared to five patients in the placebo group (p < 0.02). D-dimers and fibrin split products were significantly less prevalent in the epsilon-aminocaproic acid group (at 4 hours: 0/20 versus 7/16, p < 0.002 and 5/20 versus 12/19, p < 0.05, respectively). None of the patients had a perioperative myocardial infarction or cerebrovascular accident. The prophylactic administration of epsilon-aminocaproic acid results in a significant decrease in blood loss in patients undergoing first-time coronary artery bypass grafting, and blood transfusion requirements are significantly less. It may be important to administer epsilon-aminocaproic acid before skin incision to be optimally effective.
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Manual cardiopulmonary resuscitation is currently the standard treatment for cardiac arrest patients both in and out of the hospital. Accumulated experimental and anecdotal clinical evidence suggests enhanced survival in patients with extreme circulatory decompensation who have been emergently supported with portable cardiopulmonary bypass. Long-term survival is possible even when application is delayed, but early institution of support after cardiac arrest in selected patients offers the best survival advantages. In our hospital this has been achieved by training a team of in-house personnel to emergently prepare, apply, and temporarily manage cardiopulmonary bypass until personnel with greater specialty training arrive. Machinery needed to perform emergency cardiopulmonary bypass is currently available in all hospitals with open heart surgery programs. Simple support is often therapeutic but can also serve as a bridge to definitive diagnostic and other therapeutic procedures. Commercial units are becoming more biocompatible and easier to use, making both wider application and more prolonged support likely in the future.
Total circulatory support for acute reversible myocardial failure is rarely used in clinical situations outside the postoperative period following cardiac surgery. We treated an 8-year-old girl who suffered acute viral myocarditis and sustained cardiac arrest requiring cardiopulmonary bypass for resuscitation. This was accomplished with the use of the portable cardiopulmonary support system (CPS), which consists of a centrifugal pump and a membrane oxygenator. This patient was placed on CPS in Hawaii and transported after 3 days to San Diego (4200 km) for further mechanical support and possible heart transplantation. Adequate cardiac function returned and CPS was stopped after 6 days. She is alive and well, attending school two and a half years after the event. Prolonged use of CPS for acute myocardial failure outside the operating room, including long distance transportation, is effective and easily accomplished with currently and widely available equipment, and should be used in acute, reversible catastrophic heart disease.
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BACKGROUND: Attempts to identify noninvasive markers of ventricular dysfunction accompanying acute rejection have been hampered by a lack of detailed simultaneous hemodynamic data. Therefore, we prospectively performed serial monitoring of detailed left and right heart hemodynamic parameters in cardiac transplant recipients at the time of routine endomyocardial biopsy to better define the physiology of the allograft heart during and after acute rejection. METHODS AND RESULTS: To better assess the pathophysiology of the rejection process, 18 cardiac transplant patients were prospectively studied by serial right heart micromanometer catheterization and digital image processing at the time of routine endomyocardial biopsy. Eleven patients had 18 episodes of rejection. Studies of baseline (negative biopsy preceding rejection), rejection (acute moderate rejection), and resolved (first negative biopsy after rejection) states were compared. Seven patients who did not experience an episode of rejection served as the control group. Right ventricular minimum and end-diastolic pressures increased from baseline values of 0.9 +/- 3.2 and 6.9 +/- 3.7 mm Hg, respectively, to 3.2 +/- 5.5 and 9.9 +/- 6.6 mm Hg, respectively, with rejection (both variables, p less than 0.05) and remained elevated despite histological resolution of rejection (4.3 +/- 5.5 and 10.0 +/- 7.1 mm Hg, respectively; p less than 0.05 for both variables compared with baseline values). Concurrently, right ventricular end-diastolic volumes (133 +/- 29, 119 +/- 27, and 114 +/- 30 ml; baseline, rejection, and resolved, respectively) and left ventricular end-diastolic volumes (133 +/- 24, 117 +/- 20, and 113 +/- 30 ml; baseline, rejection, and resolved, respectively) significantly decreased during rejection and remained decreased after resolution of rejection (rejection and resolved compared with baseline values, p less than 0.05). Right ventricular chamber stiffness (0.055 +/- 0.035, 0.085 +/- 0.057, and 0.092 +/- 0.076 mm Hg/ml; baseline, rejection, and resolution, respectively; rejection and resolved compared with baseline values, p less than 0.05) increased with rejection and remained elevated after resolution of rejection. Right ventricular peak filling rate also increased from a baseline value of 2.48 +/- 0.45 to 2.76 +/- 0.63 ml end-diastolic volumes per second with rejection (p less than 0.05). Elevation of right ventricular filling pressures, peak filling rate, and chamber stiffness with a concomitant decrease in end-diastolic volume is consistent with a restrictive/constrictive physiology. Mean arterial blood pressure and systemic vascular resistance were elevated after the resolution of rejection (compared with either rejection or baseline values, p less than 0.05) associated with a higher mean daily dose of prednisone (resolved compared with either baseline or rejection values, p less than 0.05). The control group experienced a time-dependent increase in mean and diastolic systemic arterial pressures (both comparisons, p less than 0.05) without detectable diastolic dysfunction. CONCLUSIONS: Persistence of biventricular diastolic dysfunction may be due to an irreversible effect of rejection, although multifactorial changes in left ventricular afterload occur that may complicate serial assessment of ventricular function.
A portable cardiopulmonary bypass system that can be rapidly deployed in a nonsurgical setting using nursing staff was used in 38 patients with cardiovascular collapse refractory to ACLS protocol. Percutaneous or cutdown cannulation sites were: femoral vein-femoral artery (n = 18), right internal jugular vein-femoral artery (n = 2), right atrium-ascending aorta (n = 12), or a combination approach (n = 4). Two patients could not be cannulated. Patient diagnoses were pulmonary emboli (n = 3), failed coronary angioplasty (n = 7), myocardial infarction with cardiogenic shock (n = 5), trauma (n = 7), aortic stenosis (n = 2), postcardiotomy deterioration (n = 10), deterioration after cardiac transplantation (n = 2), cardiomyopathy with shock (n = 1), and ruptured ascending aortic dissection (n = 1). Ninety-five percent of patients (36 of 38) were successfully resuscitated to a stable rhythm. Eight diagnostic procedures (coronary angiography, n = 4; pulmonary angiography, n = 3; and aortography, n = 1) were performed while patients were on cardiopulmonary support. Early deaths resulted from massive hemorrhage (n = 8), inability to cannulate (n = 2), and irreversible myocardial injury (n = 10). Sixty-six percent (24 of 36) of patients successfully cannulated underwent conversion to standard cardiopulmonary bypass with attendant operative procedure or placement of ventricular assist device or total artificial heart. Fifty percent (18 of 36) of patients cannulated were successfully weaned from cardiopulmonary support, and 17% (6/36) are long-term survivors.(ABSTRACT TRUNCATED AT 250 WORDS)
Our 6-year experience with ventricular assist devices was reviewed to determine variables associated with improved survival. Forty-three patients (mean age 62 +/- 14 years) were supported after balloon pumping and pressors proved inadequate. Twenty-eight patients could not be weaned from cardiopulmonary bypass, 12 patients deteriorated in the intensive care unit after cardiac surgery, and three had a bridged to transplantation. Overall, 47% (20/43) of patients could not be weaned from the ventricular assist devices, and 26% (11/43) were weaned but died before discharge, resulting in a hospital mortality rate of 72% (31/43). The remaining 28% (12/43) of patients were discharged and have survived 9 to 62 months. Early institution of ventricular assist devices (p less than 0.01), use of biventricular support (p less than 0.01), use of ventricular assist devices as a bridge to transplantation (p less than 0.05), and increased operator experience (p less than 0.05) were associated with improved survival. When patient and disease-related variables were analyzed, only age less than 60 years (p less than 0.01) and unexpectedly preoperative myocardial infarction associated with shock (p less than 0.05) were related to improved survival. Death was caused by insufficient ventricular recovery, stroke, multiple organ system failure, sepsis, or a combination of these complications. During long-term follow-up, two patients have died of congestive heart failure, and one is significantly impaired from a stroke. Two other patients are functional class III and seven patients are class I. Although hospital mortality was high (72%), the use of ventricular assist device support resulted in overall "long-term" survival of a significant percentage (28%) of patients, 47% (8/17), in the past 12 months, all of whom would have died without it. Therefore we currently recommend a trial of ventricular assist devices support for most patients who fail to be weaned from cardiopulmonary bypass, deteriorate in the perioperative period, and as a bridge to transplantation. Long-term survival is determined by the complications from ventricular assist devices support and functional status of the remaining myocardium.
Mechanically assisted recovery from shock and long-term survival of nontransplant patients with acute noncoronary myocardial decompensation have not been previously reported. We treated nine patients (aged 8 to 53 years) who were referred with acute nonischemic cardiogenic shock (pulmonary capillary wedge greater than 20, cardiac index less than 1.5 L/min/m2, mean blood pressure less than 60 mm Hg, ejection fraction less than 0.3%). Eight patients had viral prodromes, and one patient was peripartum. All patients' lungs were mechanically ventilated, and pharmacologic support failed in all patients. Two patients received steroids. All received mechanical circulatory support. Seven were initially supported with intraaortic balloon counterpulsation pumps. Two patients recovered with intraaortic balloon counterpulsation pumps alone (3 days and 4 days). Four patients received left ventricular assist devices (3, 7, 10, and 79 days), and two received biventricular support devices (10 days and 14 days). One patient was supported with extracorporeal femoral vein-to-femoral artery bypass for 6 days. Four patients required dialysis (4 days to 5 weeks). Seven patients underwent myocardial biopsies, of which three demonstrated acute myocarditis. All patients recovered ventricular function (ejection fraction greater than 0.55%), and all are New York Heart Association functional class I, 7 months to 4 1/2 years after support. Mechanical circulatory assist devices may be lifesaving for patients with acute nonischemic myocardial decompensation. Patients should be supported for at least 2 weeks before transplantation is considered.
Optimal support for immediate cardiac allograft failure is unknown. With the introduction of heparin bonded extracorporeal membrane oxygenated circuits, prolonged cardiopulmonary support is possible. The authors report a case that involved 2 days of right atrial to ascending aorta extracorporeal membrane oxygenated support after immediate donor organ failure prevented the patient from exiting bypass. Continued deterioration in cardiac function led to an attempt at conversion to a total artificial heart as a bridge to retransplant. However, this procedure resulted in transbronchial exsanguination and recipient death. The autopsy showed pulmonary thrombosis with infarction and hemorrhage. The authors recommend caution in the use of extracorporeal membrane oxygenated support for patients with immediate and profound graft failure because of the increased risk of stasis thrombosis and pulmonary infarction due to sluggish pulmonary and left atrial blood flow. Instead, institution of total artificial heart or biventricular support may be preferable as the risks of thrombus and infarction are less.
Most centers consider medically unresponsive pulmonary hypertension an absolute contraindication to orthotopic cardiac transplantation because the alternative surgical therapy, heterotopic graft placement, is associated with decreased survival, although most patients normalize their pulmonary hemodynamics postoperatively. Orthotopic transplantation in patients with elevated, but responsive pulmonary pressures, also is associated with an increased operative mortality rate and decreased long-term survival. The authors present the case of a patient with medically unresponsive pulmonary hypertension who was mechanically supported in an effort to improve his orthotopic transplant candidacy and decrease his risk. After informed consent, a HeartMate left ventricular assist device (LVAD) was inserted and the pulmonary hemodynamic response was monitored. Immediately before LVAD insertion, the pulmonary artery pressure (PA) was 74/28 mmHg with a transpulmonary gradient (TPG) of 28 mmHg, and a pulmonary vascular resistance (PVR) of 6.6 Wood units, despite prolonged dobutamine, milrinone, and prostaglandin E1 infusions. After 10 weeks of LVAD support, pressure and resistance improved; pulmonary artery pressure was 28/15 mmHg, transpulmonary gradient was 15 mmHg, and pulmonary vascular resistance was 2.8 Wood units. This patient subsequently underwent an uneventful orthotopic heart transplant. At 1 year after transplantation, pulmonary artery hemodynamics were normal (PA 34/14 mmHg, TPG at 8 mmHg, and PVR at 1.5 Wood units). The authors recommend the consideration of LVAD placement in patients with medically unresponsive pulmonary artery hypertension to assess PA responsiveness and improve the patient's orthotopic cardiac transplant candidacy and decrease the operative risk. However, several weeks may be needed for normalization of pressure and resistance.