Some determinants of quality and yield in the isolation of adult heart cells from rat.

We investigated the effect of changes in perfusate substrate and Ca content on the quality and yield of isolated adult rat heart cells. When 1 mM Ca was added to the recirculating perfusate 15 min after collagenase addition, the ATP level of cells in the heart 15 min later, and their morphology in histological section, was no different from when no Ca was added back. The cells subsequently isolated were of similar yield, but a greater percentage were rod-shaped, compared with cells isolated without Ca restoration to the perfusate. Increased yield could be obtained by including substrates in the perfusate in addition to glucose. Either fatty acids or amino acids were effective. We conclude that: (1) all cells in the heart are Ca tolerant at the end of enzyme perfusion; (2) the presence of substrates in addition to glucose can help cells survive the isolation process.

Poststernotomy fractures and pain management in open cardiac surgery.

STUDY OBJECTIVES: To assess whether (1) there is an increased incidence of sternal fractures associated with internal mammary artery (IMA) revascularization in open heart surgery and (2) there is a higher incidence of pain in postoperative patients with sternal fractures. METHODS: Two hundred eighty-eight consecutive adult patients who had undergone cardiac surgery underwent median sternotomy from 1989 to 1991. IMA revascularization was used in 94 patients. The remainder underwent conventional saphenous vein graft (SVG) revascularization or other open cardiac procedure. The sternum was checked for fracture at the time of chest-wall closure. Lung volumes, arterial blood gases, respiratory rate, and oxygen requirements were measured before and after pain relief by intravenous or epidural analgesia. RESULTS: Of 288 consecutive median sternotomies, there were a total of 24 sternal fractures. IMA harvesting was associated with a significantly greater incidence of sternal fractures. In the 94 patients in whom IMA mobilization was used, there were 16 fractures; in the remaining 194 cases, there were 8 fractures (p < 0.007). Twenty-one of 24 patients were not seriously affected by their sternal fractures, whereas 3 patients suffered major respiratory compromise due to postoperative pain. Epidural analgesia was effective treatment for these three cases of severe sternal fracture pain and was not associated with any adverse consequences. All three patients had significant improvement in their respiratory condition after epidural analgesia was instituted. Respiratory rate decreased from 27 +/- 3 to 18 +/- 0.3 breaths/min (p < 0.001) and end maximum inspired volume increased from 700 +/- 1 mL to 1,525 +/- 275 mL. CONCLUSIONS: The use of sternal retraction devices for IMA harvesting in coronary bypass procedures results in an increased incidence of sternal fractures when compared with conventional SVG bypass procedures. Although most sternal fractures are well tolerated, some patients with fractures can become a significant pain management problems. Epidural analgesia is a safe and effective treatment for severe pain associated with sternal fractures and provided improved postoperative pulmonary function.

The fate of aortic valve homografts 12 to 17 years after implantation.

Results of long-term follow-up of an early cohort of patients receiving aortic valve homografts for aortic stenosis and aortic insufficiency are presented. All patients were operated upon by a single surgeon from 1966 to 1971. Eighty-three patients underwent insertion of 85 homograft aortic valves. Homografts were sterilized with either betapropiolactone (39 valves) or gamma irradiation (41 valves) and were inserted following storage in nutrient medium (16 valves) or after cryopreservation (51 valves). All homograft valves were sutured in the subcoronary position using a freehand technique. There was a 55 percent 15-year actuarial patient survival and a 16 percent 15-year actuarial homograft survival in this cohort. Homograft valve failure occurred gradually allowing the patients to be observed until they developed hemodynamic compromise at which time elective valve replacement was performed.

Diagnosis and management of the hypothyroid patient with chest pain.

A retrospective analysis of 38 patients undergoing cardiac catheterization with the diagnoses of hypothyroidism and chest pain revealed 23 to be euthyroid while receiving replacement therapy and 15 to be hypothyroid. Cardiac index was significantly reduced (p less than 0.01) in hypothyroid and euthyroid patients with thyroxine values between 4 and 7 micrograms/dl (2.8 +/- 0.7 and 3.0 +/- 0.9 L/min/m2, respectively), compared to euthyroid patients with thyroxine values greater than 7 micrograms/dl with or without coronary artery disease (4.0 +/- 1.2 and 4.0 +/- 0.7 L/min/m2, respectively). Ten hypothyroid patients underwent coronary artery bypass. There were no deaths, and only one patient required prolonged postoperative intubation. With a mean follow-up of 36 months, there have been no myocardial infarctions and one late death, which occurred at 7 years secondary to stroke. We conclude that preoperative thyroid replacement therapy is theoretically dangerous and may not significantly improve hemodynamics until full replacement is achieved. Coronary bypass grafting can be performed safely despite hypothyroidism with excellent early results.

Computerized fluoroscopy: new technique for the noninvasive evaluation of the aorta, coronary artery bypass grafts, and left ventricular function.

A computerized fluoroscopy system has been developed on the basis of real-time digital processing of x-ray transmission data from traditional image-intensified fluoroscopy equipment. High-quality visualization of any part of the arterial system is obtained following intravenous injection of 0.5 to 0.75 ml/kg of iodinated contrast materials. This report describes the use of this technique to evaluate the aortic arch, left ventricular function, and coronary artery bypass graft patency. Fifty intravenous studies were performed in 25 patients. Among 20 patients with coronary artery bypass grafts, computerized fluoroscopy correctly identified 11 of 15 patent grafts and 11 of 11 occluded grafts as confirmed by standard coronary arteriography in 11 of these patients. Unlike computerized tomography, our technique gives a longitudinal view of the bypass graft much like direct coronary angiography. Aortic arch studies included demonstration of a right aortic arch with a small left subclavian artery, a coarctation, and a normal aortic arch in a trauma patient with a wide mediastinum. Segmental wall motion abnormalities were clearly identified by a modification of the technique which produces a negative outline on the ventriculogram in dyskinetic segments. Ejection fractions may be calculated by determining the amount of iodine in the ventricle in systole and diastole. This technique may also be used to evaluate carotid disease and peripheral vascular disease in patients undergoing coronary artery bypass procedures. Computerized fluoroscopy, therefore, allows evaluation of the entire cardiovascular system by the relatively noninvasive technique of intravenous angiography.

Incomplete recovery of working heart function after twenty-four-hour preservation with a modified University of Wisconsin solution.

BACKGROUND AND METHODS: This study was designed to determine the function of isolated rabbit hearts after static preservation with modified University of Wisconsin solution for 24 hours. Commercially available University of Wisconsin solution, modified with CaCl2 1 mmol/L and 2,3-butanedione monoxime 30 mmol/L, was used as the preservative. After flushing the coronary vasculature with medium, hearts were submersion stored at 1 degree C to 4 degrees C. After preservation, isolated heart function at 37 degrees C was quantified for 30 minutes in a non-ejecting mode and for 4 hours ejecting at a physiologic workload. Fresh control hearts (n = 5) and University of Wisconsin solution-preserved hearts (n = 6) were studied. RESULTS: Nonworking (non-ejecting) left ventricular function of the two groups did not differ, except for peak rate of left ventricular pressure development which was higher for the University of Wisconsin solution hearts than for controls. When the hearts were subjected to a physiologic workload, however, left ventricular function of the two groups differed significantly. Three of the six University of Wisconsin solution hearts failed before the 4-hour perfusion end point, whereas all five control hearts maintained stable working function for the full 4 hours. The University of Wisconsin solution hearts, while in the ejecting mode, exhibited significantly impaired function. Mean values were as follows (p < 0.05): left ventricular systolic pressure (in millimeters of mercury), control 105 +/- 1, University of Wisconsin solution 86 +/- 4; peak rate of left ventricular pressure development (in millimeters of mercury per millisecond), control 3.33 +/- 0.11, University of Wisconsin solution 2.39 +/- 0.24; cardiac output (in milliliters per minute per gram), control 400 +/- 25, University of Wisconsin solution 288 +/- 26; stroke work (in milliJoules per gram), control 20.1 +/- 1.3, University of Wisconsin solution 11.9 +/- 1.1; left ventricular end-diastolic pressure (in millimeters of mercury), control 5.4 +/- 0.3, University of Wisconsin solution 10.2 +/- 1.3; peak aortic flow rate (in milliliters per minute), control 946 +/- 9, University of Wisconsin solution 659 +/- 44; millimoles of lactate produced in 30 min/Joule stroke work, control 0.50 +/- 0.06, University of Wisconsin solution 6.99 +/- 0.37. CONCLUSIONS: These results indicate that (1) hypothermic storage in this modified University of Wisconsin solution does not preserve hearts sufficiently to support a physiologic workload for an extended period and (2) assessment of post-preservation function with a non-ejecting heart model does not accurately predict the ability of the preserved heart to support a physiologic workload.

Posttransplantation function of hearts preserved with fluorochemical emulsion.

This study was designed to determine whether the novel perfluoroperhydrophenanthrene-egg yolk phospholipid emulsion, APE-LM, was an effective oxygen carrier for long-term hypothermic heart preservation. We postulated that hearts preserved with APE-LM would be well oxygenated during 24-hour preservation and that reperfusion of such hearts with blood would not produce functional or metabolic evidence of myocardial ischemia. Four groups of rabbit hearts were studied (n = 7 per group): fresh controls: nonpreserved, nontransplanted hearts; surgical controls: fresh hearts transplanted heterotopically for 75 minutes before explant and study for 4 hours as isolated working hearts perfused at 37 degrees C; crystalloid-preserved: hearts preserved with crystalloid medium, followed by transplantation and isolated heart perfusion; APE-LM-preserved: hearts treated as those in the crystalloid-preserved group, but preservation was with medium containing APE-LM emulsion (10 ml/dl). Preservation was with continuous coronary perfusion at 18 mm Hg pressure, 12 degrees C, and oxygen tension 838 +/- 11 mm Hg. During preservation, APE-LM hearts had significantly higher pyruvate consumption, and correspondingly higher oxygen consumption, than that of crystalloid hearts. No significant differences were found among fresh controls, surgical controls, and APE-LM-preserved hearts with respect to contractile or output function, oxygen consumption and efficiency indexes, or lactate production during in vitro perfusion. Left ventricular peak systolic pressure and peak rate of pressure development were significantly lower for crystalloid-preserved hearts than for fresh and surgical controls. Left ventricular end-diastolic pressure of crystalloid-preserved hearts was higher than that of the other three groups. The data indicate that rabbit hearts in this model were well preserved with APE-LM and that this emulsion produced better recovery of function than did crystalloid preservation, possibly as a consequence of the high oxygen delivery by the fluorocarbon during preservation.

Importance of substrate enhancement for long-term heart preservation.

These experiments tested the hypothesis that addition of pyruvate to a preservation medium would improve postpreservation cardiac function as quantified in an isolated working heart model after heterotopic transplantation. Four groups of rabbit hearts were studied (n = 5 per group): fresh controls, fresh hearts perfused as isolated working hearts; surgical controls, fresh hearts transplanted heterotopically and reperfused with blood for 75 minutes before being studied as isolated hearts; preserved without pyruvate, hearts perfusion-preserved with oxygenated extracellular-type crystalloid medium; preserved with pyruvate, same same as the group without pyruvate, but medium contained 20 mmol/L pyruvate. After preservation, the hearts in the two preserved groups were transplanted and studied as isolated hearts. Total ex vivo time for the preserved hearts was 24.5 +/- 0.2 hours. During preservation, glucose was not consumed by hearts in either preserved group. Pyruvate was used by the hearts to which it was provided (22.9 +/- 2.7 mumol pyruvate x hour-1 x gm dry weight-1). Performance of transplanted surgical control hearts was not significantly different from that of fresh controls. Function of the pyruvate-preserved hearts was similar to that of the fresh and surgical controls except that left ventricular peak systolic pressure and peak rate of pressure development were lower and that left ventricular end-diastolic pressure was higher for the pyruvate-preserved hearts. The hearts preserved without pyruvate had significantly lower compliance and function compared to the other three groups, which was evident in all indexes of contractility and output. We conclude that hearts preserved with pyruvate-containing crystalloid medium had better postpreservation, posttransplantation function than hearts preserved without pyruvate, although there was slight loss of compliance and decreased contractile function in the pyruvate-preserved hearts compared to controls.

Digital subtraction angiography and B-mode ultrasonography for abdominal and peripheral aneurysms.

Thirty-two patients suspected of having intraabdominal and/or peripheral aneurysms were evaluated by digital subtraction angiography (DSA) and B-mode ultrasonography to determine whether diagnostic accuracy and operative management could be improved by this combination of preoperative studies. Abdominal B-mode ultrasonography accurately diagnosed most primary aortic aneurysms and correctly determined their size (93%) but missed iliac artery aneurysms in 75% of cases. Failures resulted from severe ileus and the inability to scan the intrapelvic iliac vessels. Abdominal ultrasound studies were false positive for aortic pseudoaneurysms in two of four cases. DSA correctly identified all but one intra-abdominal aneurysm but did not always correctly determine their size because of intraluminal clot. DSA identified a number of associated peripheral vascular lesions, which ultrasonography could not. All primary peripheral aneurysms were correctly diagnosed by ultrasound, but nearly half of the ultrasound studies were false positive for femoral pseudoaneurysms. DSA correctly identified all peripheral aneurysms and at the same time provided anatomic information about vessels proximal and distal to these lesions needed for surgical planning. Digital subtraction angiography combined with ultrasonography is diagnostically accurate and provides adequate anatomic information for planning surgical management of these aneurysms.

Intra-arterial digital angiography: a new diagnostic method for determining limb salvage bypass candidates.

Twenty patients with chronic arterial disease of a lower extremity underwent standard angiography to determine whether distal bypass surgery could be performed for limb salvage (seven had pain at rest and 13 had breakdown of ischemic skin). Standard angiography provided anatomic detail of the aortoiliac and proximal femoral arteries in all cases, but even with 7 minutes of cuff-induced reactive hyperemia, angiography failed to demonstrate the status of the tibial vessels and the plantar arcade.l Digital subtraction angiography (with intra-arterially injected contrast medium) demonstrated a patent popliteal artery with at least one patent tibial vessel communicating with the distal arcade in 14 of 20 ischemic extremities (70%). Intra-arterial digital angiography (IDA) confirmed absent distal runoff or unreconstructable tibial arterial segments with absent plantar arch communications in six limbs (30%). Fourteen patients underwent distal artery bypass because of additional information provided by IDA (femoropopliteal, 7; femorotibial-peroneal, 4; sequential, 3). Three of the remaining six patients with occluded or unreconstructable distal disease had amputations, and three underwent local profundoplasty. Intraoperative angiograms confirmed the patency of occult arteries in the distally reconstructed limbs. This small series suggests that failure to visualize distal vasculature in ischemic patients by standard angiography is usually a technical problem and that bypass surgery is possible in many patients who might otherwise be considered for amputation.

Postoperative occlusion after carotid endarterectomy.

Noninvasive testing (Doppler imaging and spectral analysis of carotid flow) was performed in 70 symptomatic patients who required unilateral carotid endarterectomy. Angiographic correlations were made with the noninvasive tests before surgery, and postoperatively hemodynamic changes were determined during a three-year follow-up period. Postoperative stenosis occurred in 9% (3% early and 6% late) of the patients. Clinical progression on the unoperated side (new symptoms or bruits) occurred in 15 patients. Ten of these 15 patients had significant hemodynamic progression of disease in the unoperated carotid as well. Clinically occult hemodynamic progression of disease on the unoperated side was detected by noninvasive testing in four of the cases. Neurological complications resulting from postoperative occlusion occurred in two cases.

Femorotibial bypass grafts with sequential technique. Clinical results.

Twenty-three patients (mean age, 71 years) have undergone femorotibial bypass grafting with a sequential side-to-side popliteal anastomosis since 1975, 96% because of threatened limb loss. Twenty-one grafts were of autogenous saphenous vein and two were composites of prosthesis and vein. Ankle-brachial indices increased from 0.40 +/- 0.27 to 0.84 +/- 0.36. Intraoperative flow measurements showed a 40% to 75% augmentation in flow with the sequential anastomosis. Patients who required amputation in the early postoperative period because of graft failure failed to show improvement in ankle indices and did not manifest healing of their ischemic ulcerations. Nineteen of 23 limbs (83%) were salvaged by operation. Follow-up ranged from two to 50 months (mean, 23 months). Graft patency calculated by the life-table method was 74% at one year, 68% at two years, and 62% at four years.

Improved myocardial function using cardiopulmonary support in resuscitation for hemorrhagic shock.

OBJECTIVES: To clarify the pathophysiologic characteristics of hemorrhagic shock and to assess methods of resuscitation. DESIGN: An animal experiment using sheep subjected to hemorrhagic shock and fibrillation to compare various resuscitation techniques. SETTING: An experimental laboratory setting meant to simulate hemorrhagic shock secondary to trauma. STUDY GROUPS: Group 1 animals (n = 6) were controls that were not subjected to shock and fibrillation. Group 2 animals (n = 6) were subjected to shock and fibrillation and were resuscitated with volume replacement. Group 3 animals (n = 6) were also subjected to shock and fibrillation but were resuscitated with epinephrine hydrochloride infusion. Group 4 animals (n = 6) were subjected to shock and fibrillation but were resuscitated with cardiopulmonary support. INTERVENTIONS: The shock was to a mean arterial pressure of 25 mm Hg for 1 hour followed by 5 minutes of fibrillation. Group 2 animals were resuscitated for 1 hour. Group 3 animals were supported for 6 hours on epinephrine after the shock period. Group 4 animals were supported for 1 hour on cardiopulmonary support, then were observed for another 5 hours. All animals were sedated and intubated, and a median sternotomy was performed. MAIN OUTCOMES MEASURED: Survival, hemodynamic function, lactate production, myocardial blood flow, and water content. RESULTS: Group 1 sheep showed no detrimental effects in any of the measured variables. Group 2 sheep could not be resuscitated. Group 3 sheep could be supported with epinephrine but had a 60% depression in left ventricular function and an ultimately high mortality rate (67%) when the infusion of epinephrine was discontinued. Group 4 sheep had a 100% survival rate and only a 20% deterioration in left ventricular function. CONCLUSIONS: Cardiopulmonary support improves survival and preserves left ventricular function compared with volume resuscitation with or without inotropic support in this model of hemorrhagic shock.

Arterial graft infections. Delayed v immediate vascular reconstruction.

We evaluated the treatment and clinical outcome of 20 patients with major abdominal vascular graft infections and found that immediate reconstruction of arterial inflow to the lower extremities after complete removal of contaminated graft material may not always be necessary or advisable. Patients were treated by the following categories: group 1, graft removal with immediate vascular reconstruction (seven patients, two aortoiliac and five aortofemoral grafts); group 2, graft removal with delayed vascular reconstruction (13 patients, three aortoiliac, five aortofemoral, and five extra-abdominal grafts). The mortality (57%) and the incidence of major amputation (14%) were highest when immediate vascular reconstruction was attempted. Patient survival, the incidence of recurrent graft infection, and the need for major amputation were favorably altered with delayed reconstruction even when prosthetic material was used.

Comparison of survival in cardiac surgery at a Veterans Administration hospital and its affiliated university hospital.

Survival data were reviewed for 3330 open cardiac procedures from 1975 through 1984 at the William S. Middleton Memorial Veterans Hospital, Madison, Wis, and the University of Wisconsin Hospitals and Clinics, Madison. Respective operative survivals were 98.6% and 98.7% for myocardial revascularizations with vein graft or internal mammary artery (CABG), 96.2% and 96.8% for CABG reoperation, 97.8% and 95.9% for aortic valve replacement, 96.3% and 90.3% for aortic valve replacement plus CABG, 100.0% and 94.9% for mitral valve replacement, and 100.0% and 82.9% for mitral valve replacement plus CABG. There were no significant differences in six-year survival curves between hospitals despite threefold differences in average annual caseload (88 vs 294). This suggest that residency-directed cardiac surgery programs can function equally as well at a Veterans Administration hospital as at an affiliated university hospital.

Use of Carmeda-coated femoral-femoral bypass during repair of traumatic aortic pseudoaneurysms.

OBJECTIVE: To compare the results and outcomes of three different approaches to posttraumatic pseudoaneurysm repair: clamp and sew, left heart bypass, and the most recent approach, cardiopulmonary support using femoral-femoral bypass. DESIGN: Retrospective series. SETTING: A university-based, level 1 trauma center. PATIENTS: Forty-two consecutive patients treated for posttraumatic aortic pseudoaneurysm whose mean (+/- SEM) Injury Severity Score was 37 +/- 1.7. INTERVENTION: Methods of repair included clamp and sew in nine patients, left heart bypass in 24 patients, and cardiopulmonary support in nine patients. METHODS: Student's t test was used to compare interoperative blood loss, need for blood transfusion, and aortic cross-clamp time. Complications and mortality were also reviewed. RESULTS: Mean (+/- SEM) aortic cross-clamp time for clamp and sew was 28.1 +/- 3.3 minutes vs 52.5 +/- 3.7 for left heart bypass and 49.3 +/- 5.6 for cardiopulmonary support. Blood loss and the need for transfusion were comparable between groups. Complications were also comparable. CONCLUSION: Femoral-femoral cardiopulmonary support is safe to use, has a very low risk of complications, and should provide protection for the spinal cord during aortic repair. We encourage a randomized prospective trial to determine if cardiopulmonary support has a significantly lower rate of paraplegia than the clamp- and -sew technique.

Patient selection and results of simultaneous coronary and carotid artery procedures.

The high incidence of severe coronary artery disease in patients with symptomatic carotid artery disease makes careful evaluation of both carotid and coronary systems important to the successful short-term and long-term management of these patients. We have established guidelines for patient evaluation and procedure selection based on symptomatic assessment of each system, supplemented by angiographic and hemodynamic data. With this information, three operative groups are established: (1) carotid artery operation first or alone, (2) coronary artery bypass grafting first followed by carotid artery operation, and (3) simultaneous carotid artery and coronary artery bypass procedures. The benefit of this selection process has been shown by the low operative mortality in each group. This report presents our selection process and evaluates the results for 21 patients in the group having simultaneous carotid and coronary artery procedures.

Intrapulmonary steal complicating repair of tetralogy of Fallot.

A patient with total occlusion of the distal right pulmonary artery secondary to the performance of a Waterston shunt is reported. A nearly fatal intrapulmonary steal occurred at the time of corrective operation when an attempt was made to revascularize both pulmonary arteries.

Use of a heat exchanger to prevent hypothermia during thoracic and thoracoabdominal aneurysm repairs.

Hypothermia is a common unplanned occurrence in many patients undergoing repair of thoracic and thoracoabdominal aneurysms. Many undesirable side effects of hypothermia have been documented, including decreased cardiac output, conduction abnormalities, and blood coagulopathies. We have developed a simple system that incorporates a Sci-Med Biotherm heat exchanger into our left heart bypass circuit. This provides us with the ability to actively rewarm the patient safely and efficiently. This study looks at 16 consecutive patients undergoing repair of thoracic or thoracoabdominal aneurysms. In the 9 patients in whom the heat exchanger was used, there were no adverse effects related to the heat exchanger. All patients had significantly higher temperatures at the conclusion of the procedure than the 7 patients in whom the heat exchanger was not used.

Pericardial patch repair of left ventricular aneurysm.

Infectious complications associated with the use of Teflon felt buttresses in left ventricular aneurysm repair may result in serious morbidity. Use of an autologous pericardial patch is an alternative approach that should be considered. The technique, which we have used in 4 patients, is described.