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Biomedical subjects

O W Isom

Publications and source records attributed to O W Isom.

At least 55 records · Page 3Linked to original sources
PubMed1994

Glutaraldehyde treated autologous pericardium in complete repair of tetralogy of Fallot.

Pericardium has been used for decades to facilitate the repair of tetralogy of Fallot (TOF). The impact of glutaraldehyde preserved autologous pericardium when used as a right ventricular outflow tract (RVOFT) patch in TOF was analyzed in 36 consecutive children undergoing complete transventricular repair. In 18 (group I) the pericardium was treated in conventional fashion (harvested and preserved in saline solution). In the other patients, the pericardium was treated in 0.625% glutaraldehyde solution for 20 minutes and then washed in saline prior to being implanted as an RVOFT patch (group II). The perioperative (prior to hospital discharge) as well as the 6-month postoperative Doppler echocardiograms were assessed with 100% follow-up. The studies were evaluated and graded by blinded observers for the presence and severity of an RVOFT dilatation (+0 to +4) relative to the size of the aortic valve annulus. The age of patients in group I and group II (29 months, 34 months) were similar as was the incidence of transannular patching (44%, 41%). Postrepair hemodynamics revealed no significant difference in the right ventricular/left ventricular pressure ratios (42%, 41%) or in the systolic RVOFT pressure (24 mmHg, 29 mmHg). The predischarge echocardiograms showed no outflow tract (OFT) dilation in either group. There was no morbidity or mortality in either group. At approximately 6 months postoperatively (6.2 mo, 5.7 mo), 72% of group I patients had RVOFT diameters that were larger (+1, +2) than the predischarge diameters when reviewed by three observers. In group II there was a single patient with dilatation of the RVOFT and this graded as +1.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1994

Internal mammary artery is a safe conduit for repeat coronary revascularization.

The safety of repeat coronary revascularization using the internal mammary artery (IMA) as a conduit was examined in patients undergoing repeat revascularization between January 1988 and June 1991. The 71 patients in whom the IMA was used as one of the conduits were compared with 57 patients in whom only vein grafts were used. Patients undergoing IMA grafts were likely to have more vessels revascularized. Nevertheless, there were no significant differences in outcome between the two groups as measured by complications or period of hospitalization. In a multivariate analysis, the only independent predictor of poor outcome was emergency surgical treatment. The current study would indicate that IMA grafts are safe in the setting of repeat coronary revascularization.

Aged↗
PubMed1994

Neutrophil leukotriene generation increases after cardiopulmonary bypass.

BACKGROUND: Leukotriene B4 has been shown to play a role in the systemic inflammatory response after cardiopulmonary bypass in experimental animal models; however, the importance of this mediator in human beings undergoing cardiac operations has not been established. METHODS: The neutrophils of ten patients undergoing coronary artery bypass grafting with cardiopulmonary bypass were studied for their ability to generate leukotrienes at the time of the induction of anesthesia, the institution of cardiopulmonary bypass, the removal of the aortic crossclamp, at the end of the operation, on admission to the intensive care unit, and on postoperative days 1 and 2 RESULTS: After cardiopulmonary bypass, the generation of chemotactic leukotrienes rose significantly and remained elevated on the first postoperative day compared with prebypass values (prebypass 133.8 +/- 10.7 versus postbypass 192.7 +/- 19.2 [p < 0.05] and first postoperative day 196.6 +/- 13.8 [p < 0.05]). The increases in plasma complement and lactoferrin levels, although significant, were not sustained. In addition to the neutrophil count, the potential leukotriene and oxygen radical produced was significantly increased, and this increase was correlated with postoperative length of stay. CONCLUSION: These observations support the laboratory data documenting that the rise in leukotriene generation after cardiopulmonary bypass includes human patients.

Aged↗
PubMed1993

Platelet-activating factor antagonism attenuates platelet and neutrophil activation and reduces myocardial injury during coronary reperfusion.

Platelet-activating factor (PAF) is known to be synthesized during tissue reperfusion and to be involved in the activation of platelets and neutrophils in inflammatory processes. The hypothesis of the present study is that PAF is central in the pathophysiology of myocardial reperfusion and that specific PAF receptor antagonism may reduce myocardial reperfusion injury. Utilizing an intact sheep model that involved a 90-min occlusion of the mid-left anterior descending coronary artery followed by 6 hr of reperfusion, a study group that received a specific PAF receptor antagonist (L-659,989, 5 mg/kg) 10 min before reperfusion was compared to a control group that received a saline placebo (n = 8 in each group). Coronary sinus platelet aggregating activity and neutrophil oxidative burst were studied by standard platelet aggregometry and the 2',7'-dichlorofluorescein flow cytometric assay, respectively. Left coronary flow and left ventricular functions measured as peak +/- dp/dt and stroke work were analyzed. The extent of myocardial infarction at the end of 6 hr of reperfusion was measured by standard histochemical stainings. The results demonstrated that platelets were hyperaggregable and that neutrophil oxidative burst was increased in the myocardial compartment during the first 3 hr of coronary reperfusion after 90 min of ischemia. The administration of the PAF antagonist immediately before reflow effectively prevented the activation of platelets and neutrophils. This was associated with significantly improved coronary reflow and ventricular function during the observed reperfusion period and with reduced myocardial infarct measured at 6 hr of reperfusion. We conclude that the use of a specific PAF receptor antagonist, L-659,989, immediately before controlled coronary reflow attenuated the activation of platelets and neutrophils that occurred during reperfusion. These anti-platelet and anti-neutrophil effects together with the inhibition of the known direct deleterious effects of PAF on the myocardium translated into improved ventricular function and reduced myocardial infarct.

Adenosine Diphosphate↗
PubMed1993

Cardiopulmonary bypass procedures in dialysis patients.

To determine the operative outcome of chronic renal failure patients, we retrospectively reviewed twenty-five consecutive adult patients with chronic renal failure dependent on maintenance hemodialysis (21) or peritoneal dialysis (3), who underwent cardiopulmonary bypass procedures over a five-year period in our institution. The operations included isolated coronary artery bypass grafting in 16 patients; aortic valve replacement in 3; aortic valve replacement plus mitral valve replacement in 1; aortic valve replacement, mitral valve replacement, and coronary artery bypass grafting in 2; aortic valve replacement and coronary artery bypass grafting in 1, mitral valve replacement and coronary artery bypass grafting in 1, and repair of a thoracoabdominal aortic aneurysm in 1 patient. Fourteen operations were elective, and 11 were urgent or emergent. The number of patients with good (> 0.50), fair (0.30 to 0.50), and poor (< 0.30) left ventricular ejection fractions were 13, 9, and 3, respectively. There were 0, 7, 7, and 11 patients in New York Heart Association functional classification I, II, III, and IV, respectively. All patients were dialyzed within 24 hours before operation. All but 3 patients were managed by immediate postoperative peritoneal dialysis via a Technoff catheter placed intraoperatively (18 patients) or via a preexisting Technoff catheter (4 patients). This was then switched to hemodialysis when clinical conditions stabilized. Univariate analysis of 22 preoperative and intraoperative variables, followed by a multivariate analysis with a stepwise logistic regression model, was performed using the 30-day or in-hospital operative mortality as the dependent variable.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Ischemic tolerance of the arrested heart during warm cardioplegia.

Normothermic blood cardioplegia has recently generated interest as an alternative method of myocardial protection during cardiopulmonary bypass (CPB) surgery. One disadvantage is the obligatory interruption of coronary flow during the distal coronary anastomosis. This study was designed to determine the safe normothermic ischemic time of the arrested and decompressed heart. Under normothermic CPB (37 degrees C), initial cardioplegic arrest was induced with 750 cc of warm (37 degrees C) hyperkalemic blood cardioplegia in 21 adult dogs. The heart then received warm blood cardioplegia either continuously (50 cc/min), every 5 min (250 cc each) or every 10 min (350 cc each) for a total equivalent ischemic time of 30 min (n = 7 in each group). Left ventricular pressure-volume (PV) loops were measured by micromanometer and conductance (volume) catheters before, at 60 and 90 min after aortic cross-clamping. Systolic function was measured as the preload recruitable stroke work area derived from the stroke work-end diastolic volume relationship, and the diastolic stiffness constant (k) was derived from the exponential diastolic PV relationship. The q5 min group sustained minor deterioration in diastolic function while its systolic function was well maintained during recovery. There were significant reductions in both the diastolic and systolic functions in the q10 min group. The maximum drops in the septal wall pH during aortic cross-clamping were 0.05 +/- 0.02 (not significant), 0.19 +/- 0.06 (P < 0.05), and 0.40 +/- 0.09 (P < 0.01) for the continuous, q5 min and q10 min groups, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1993

Erythropoietin in cardiac surgery.

Erythropoietin is the primary growth factor for red blood cells. A glycoprotein hormone synthesized by the kidneys, erythropoietin serves to increase red blood cell production in response to tissue hypoxia. It exerts its effect by increasing the numbers of erythroid progenitor cells in the bone marrow, and by increasing the rate at which their development is accomplished. With the introduction of recombinant erythropoietin in 1987, an important pharmacological agent became available for the manipulation of erythropoiesis. While used primarily for the treatment of the anemia of renal failure, recombinant erythropoietin has also shown usefulness in treating other types of anemias in which the endogenous erythropoietin response is insufficient. Perioperative use of the drug grew as a natural extension of this, and erythropoietin has been applied to correct preoperative anemia, augment autologous blood donation, and improve postoperative red cell recovery. Analysis of these perioperative clinical studies reveals success in these areas, but it also reveals that closer attention to the physiology of the natural response, and to the pharmacology of the recombinant product, might significantly improve results. Such an improvement in efficacy is both desirable and necessary when use of the drug is viewed in the setting of today's changing health care environment. By optimizing dosing schedules and targeting the drug to those most at risk for red cell transfusion, recombinant erythropoietin will likely become an important tool in efforts to achieve the elusive goal of bloodless cardiac surgery.

Amino Acid Sequence↗
PubMed1993

A historical perspective to current review of myocardial protection in cardiac operation.

In the discussion of the 1955 landmark study on the first series of open heart operation using the cross-circulation technique, Lillehei stated that, "The solution of many difficult problems in medicine has ultimately been simple and in most cases obvious once sufficient basic knowledge has been brought to bear on the problem." Indeed, a few surgeons have provided the guiding lights in the development of cardiac operation, but it is the acquisition of basic knowledge by thousands of surgeons and basic scientists that have contributed to its goals.

Cardiac Surgical Procedures↗
PubMed1993

Reoperative coronary artery bypass surgery. Improved preservation of myocardial function with retrograde cardioplegia.

BACKGROUND: Cardiac-related mortality remains high for reoperative coronary artery bypass graft surgery (rCABG) compared with first-time surgery (fCABG). Retrograde cardioplegia (RC) has been suggested but not proven to improve the results for rCABG. METHODS AND RESULTS: We therefore reviewed the records of 240 consecutive patients who had undergone rCABG at our institution since 1988. The interval to reoperation was 9.1 +/- 4.2 years (mean +/- SD), with a range from 0.2 to 18 years. Only 46% of grafts were patent at the time of rCABG. The incision to cardiopulmonary bypass (CPB), incision to cross-clamp (XCL), and XCL per graft time intervals were significantly prolonged compared with 100 consecutive fCABG patients operated on during the same time period. Blood utilization was also significantly increased in rCABG compared with fCABG patients. Overall operative mortality was 5.8% and 0% for rCABG and fCABG patients, respectively (P < .05). High-risk criteria (emergency surgery, angina at rest requiring intravenous nitroglycerin or intra-aortic balloon pump [IABP] support [urgent surgery], recent [<21 days] myocardial infarction, or ejection fraction < 30%) were noted in 136 rCABG patients (57%) and 28 fCABG patients (28%) (P < .001). Profound postoperative myocardial dysfunction (postoperative IABP dependence) occurred in only one of 104 low-risk patients (1%), compared with 14 of 136 high-risk patients (10%) (P < .005). Operative mortality was noted in 13 high-risk patients (9.5%) compared with one low-risk patient (1%) (P < .005). RC was used in 80 patients without complication. Postoperative IABP dependence developed in only 2 of 53 high-risk/RC patients (3.8%) compared with 12 of 83 high-risk/non-RC patients (14.5%) (P < .05). At follow-up, rCABG and fCABG patients enjoyed similar symptomatic improvement. CONCLUSIONS: We conclude that retrograde cardioplegia, possibly by minimizing the increased ischemia associated with rCABG, improves the results of rCABG, specifically in regard to preventing profound myocardial dysfunction in high-risk patients.

Coronary Artery Bypass↗
PubMed1993

The effects of warm versus cold blood cardioplegia on endothelial function, myocardial function, and energetics.

BACKGROUND: Recent interest in the use of normothermic blood cardioplegia is based on theoretical advantages over the traditional method of hypothermic myocardial protection. This study was designed to compare the effects of warm and cold blood cardioplegia on left ventricular functions and energetics and coronary responsiveness. MATERIALS AND METHODS: Two groups of mongrel dogs (n = 7 each) underwent either normothermic cardiopulmonary bypass (CPB) with continuous warm (37 degrees C) blood cardioplegia or hypothermic (26 degrees C) CPB with a single dose of cold (4 degrees C) blood cardioplegia supplemented with topical cooling during 30 minutes of aortic clamping. There was no deterioration in the endothelium-dependent and -independent coronary relaxation as tested by the infusion of acetylcholine and nitroglycerin after cardioplegic arrest for either group. At 60 minutes of reperfusion, both groups had complete recovery of left ventricular contractility as measured by the preload recruitable stroke work area derived from the measurement of the ventricular pressure (micromanometer catheter) and volume (conductance catheter) relation. The analysis of myocardial energetics in terms of the myocardial oxygen consumption-pressure volume area relation did not reveal any significant changes between the y-intercepts and the slopes of the two groups. CONCLUSIONS: For 30 minutes of aortic cross-clamp time, continuous warm cardioplegia did not provide any benefit over a single injection of cold cardioplegia in coronary endothelial and smooth muscle function, myocardial function, and energetics.

Animals↗
PubMed1993

The effects of amrinone versus dobutamine on myocardial mechanics and energetics after hypothermic global ischemia.

The effects on the postischemic myocardium of amrinone and dobutamine were studied in canine hearts that underwent 90 minutes of hypothermic (10 degrees C) arrested ischemia. In an isolated heart preparation cross-circulated by a support dog, left ventricular pressure-volume loops were collected under a constant afterload based on a mock circulatory system and a range of preload conditions controlled by a computerized servo volume pump. Dobutamine (0, 5, 10, 15 micrograms/kg per minute) and amrinone (0, 0.75, 1.5, 3.0 mg/kg) were tested in this order based on the weights of the support dogs in eight experiments. Changes in intrinsic myocardial contractility were analyzed as percent increases in the preload recruitable stroke work area from baselines. Dobutamine exhibited significant dose-related increases in the preload recruitable stroke work area. Amrinone did not produce significant increases in preload recruitable stroke work area at 0.75 mg/kg; amrinone's inotropic effect was equivalent to dobutamine, 5 micrograms/kg per minute at 1.5 mg/kg, and at the maximum dose (3.0 mg/kg) it was equivalent to dobutamine, 10 micrograms/kg per minute. The myocardial energetic efficiency was determined from the analysis of the myocardial oxygen consumption-pressure volume area relationship. The y intercept represents the basal metabolic oxygen requirement of the unloaded beating heart, and the slope is inversely proportional to the rate of energy conversion for increasing loading conditions. Dobutamine significantly increased the y intercepts, but it had no effects on the slopes. These changes demonstrate reduced myocardial efficiencies that are consistent with previous reports. Amrinone (0.75 and 1.50 mg/kg) did not result in change of the y intercepts and the slopes of myocardial oxygen consumption-pressure-volume area relationship from baseline conditions. The y intercept was increased with amrinone (3.0 mg/kg), although still not significantly higher than baseline and not to the extents of the dobutamine group. Dobutamine did not have any primary effect on coronary resistance, while amrinone significantly reduced coronary resistance in all loading conditions at 1.5 and 3.0 mg/kg. This study demonstrates that the inotropic effects of amrinone tested under this constant afterload preparation were lower than those of dobutamine. Amrinone has a superior profile of myocardial efficiency on the postischemic myocardium since it does not produce the oxygen-wasting effects of the traditional inotropic agents such as the beta agonists. This benefit, together with amrinone's coronary dilating effects, critically improves the supply/demand ratio that may be of importance in certain clinical situations.

Amrinone↗
PubMed1992

Effects of temperature and flow rate on regional blood flow and metabolism during cardiopulmonary bypass.

Eleven dogs were subjected to a 150-minute period of cardiopulmonary bypass that consisted of a high-flow, normothermic phase, a high-flow, hypothermic phase, a low-flow, hypothermic phase, and then a high-flow, rewarming phase. Regional blood flow and oxygen consumption to the brain, intestines, kidney, and hind limb were determined at baseline and at 10-minute intervals during cardiopulmonary bypass. Blood flow to the carotid artery, superior mesenteric artery, and renal artery declined significantly with hypothermic cardiopulmonary bypass whereas blood flow to the femoral artery increased significantly. Although total body oxygen consumption returned to baseline values at the end of the rewarming phase, oxygen consumption for these regions differed somewhat from their baseline values. We conclude that blood flow during hypothermic cardiopulmonary bypass is shunted to skeletal muscle, particularly with high pump flows. Additionally, the return of total body oxygen consumption to baseline after rewarming is not necessarily reflected at the regional level.

Animals↗
PubMed1992

Evaluation of an extraaortic counterpulsation device in severe cardiac failure.

A valveless, single-orifice polyurethane ventricle with a maximum stroke volume of 60 mL was implanted on the brachiocephalic artery just above the aortic arch in sheep (n = 14) to act as an extraaortic counterpulsation device. In parallel, an intraaortic balloon was placed in the descending thoracic aorta. Both devices were pneumatically driven with an intraaortic balloon pump console that was gated by the electrocardiogram to provide aortic diastolic augmentation at a stroke volume of 40 mL. To compare the efficacy of counterpulsation for each device during severe cardiac failure, biventricular block was induced by continuous infusion of esmolol (100 to 600 micrograms.kg-1.min-1), titrated to reduce aortic flow and pressure to less than 75% of baseline. Pulsatile coronary and aortic flows were recorded with ultrasonic flow probes placed around their respective vessels. Aortic root and left ventricular pressures were recorded using micromanometers. The enhancement of hemodynamic variables for both devices were compared for optimal timing conditions, which were defined as inflation set just before the dicrotic notch and deflation bordering on isovolumetric systole. The extraaortic counterpulsation device was able to significantly augment aortic and coronary flows while simultaneously decreasing left ventricular tension time index and aortic end-diastolic pressure (p less than 0.02). The intraarotic balloon pump was able to significantly reduce only tension time index (p less than 0.002) to a lesser extent that the extraaortic counterpulsation device. All analysis was performed with the paired-samples t test. The extraaortic counterpulsation device greatly improves the myocardial oxygen supply-consumption ratio of the left ventricle by increasing diastolic coronary flow and reducing left ventricular wall tension during systole.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Effects of shaving methods and intraoperative irrigation on suppurative mediastinitis after bypass operations.

To investigate the effects of the hair removal methods and intraoperative irrigation on suppurative mediastinitis after cardiopulmonary bypass operations, 1,980 consecutive adult patients over a 2-year period in our institution were prospectively randomized to manual shaving versus electrical clipping of hair before the skin incision, and to povidone-iodine solution (0.5%) versus saline solution mediastinal and subcutaneous irrigation before wound closure. The overall incidence of suppurative mediastinitis was 0.86% (17/1,980). The infectious rate was significantly higher in the manually shaven (13/990) than in the electrically clipped patients (4/990) with an odds ratio of 3.25 (95% confidence interval, 1.11 to 9.32; p = 0.024). It was also higher in the povidone-iodine group (11/990) than in the saline group (6/990), although the difference was not statistically significant (p = 0.16). Fourteen patients were treated with operative debridement with closed tube irrigation, with one failure requiring a conversion to an open wound. Two patients were successfully treated with primary open wound procedures followed by delayed muscular flap closures, and 1 patient succumbed to rapid and profound sepsis soon after open drainage. We conclude that electrical clipping is superior to manual shaving in the prevention of suppurative mediastinitis. The routine use of povidone-iodine (0.5%) irrigation was of no benefit in this study and may increase the incidence of infection due to its known suppressive effects on local leukocytes and fibroblasts. Furthermore, operative debridement with closed tube irrigation was successful in treating the majority of cases in this series.

Cardiopulmonary Bypass↗
PubMed1992

Survival analysis of octogenarian patients with coronary artery disease managed by elective coronary artery bypass surgery versus conventional medical treatment.

BACKGROUND: In view of the increasing age of the U.S. population, the use of coronary artery bypass surgery in the management of the elderly patients with coronary artery disease needs to be better defined. METHODS AND RESULTS: To evaluate the effects of medical and surgical therapy on octogenarian patients with coronary artery disease in our institution, we retrospectively reviewed 177 consecutive octogenarians who underwent cardiac catheterization over a 5-year period. Sixty-five of these patients were found to have significant coronary artery disease without severe valvular disease. Elective coronary artery bypass surgery was performed in 36 patients, whereas 29 patients were continued on maximization of medical therapy and not referred to the surgical service. Left ventricular ejection fractions (LVEF) were similar for the two groups, whereas the surgical patients had slightly higher average number of diseased coronary vessels and slightly higher levels of angina. Univariate survival analysis of 20 variables, including the choice of medical versus surgical treatment and the associated conditions, was performed by Mantel-Cox testing of the paired Kaplan-Meier product limit survival curves stratified by the subgroups of each variable. The variables found to be significant were then included in a multivariate survival analysis using the Cox proportional hazards regression model. The treatment choice, LVEF, level of angina, and presence of any aortic and/or mitral valvular disease at the time of cardiac catheterization were found to be independent prognostic indicators of survival in the follow-up period of 26 +/- 16 months. The 3-year probability of survival rates for the surgical patients and medical patients were 77.4% and 55.2%, respectively (p = 0.0294). The New York Heart Association functional class of the surgical group decreased significantly from a mean preoperative level of 3.4 +/- 0.5 to a mean level of 1.2 +/- 0.6 at the follow-up interview (p < 0.01), whereas it did not significantly change for the medical group from a baseline mean level of 2.8 +/- 1.3 to a mean follow-up level of 2.5 +/- 1.0. CONCLUSIONS: We conclude that coronary artery bypass surgery provided improved long-term survival and functional benefit compared with conventional medical treatment in a small group of octogenarian patients in our institution.

Aged↗
PubMed1992

Compositional analysis of a modified University of Wisconsin solution for extended myocardial preservation. A study of the left ventricular pressure-volume relation.

BACKGROUND: The University of Wisconsin solution (UW) has been shown to be superior to the use of traditional types of simple crystalloids in extended heart preservation. This study was designed to determine the necessity of four potentially redundant components in UW. MATERIALS AND METHODS: Forty canine hearts (n = 8 in each group) were preserved for 6 hours under hypothermic (1-2 degrees C), nonperfused conditions in unmodified UW, UW with an extracellular or reversed composition of sodium and potassium (UW-E), UW with chloride instead of lactobionate (UW-L), UW without raffinose (UW-R), and UW without hydroxyethyl starch (UW-HS). The left ventricular functions were assessed in an isolated heart preparation equipped with a computerized servo-volume pump to measure the pressure-volume relation. The systolic function was expressed in elastance derived from the end-systolic pressure-volume relation, and total ventricular performance was expressed in preload recruitable stroke work area derived from the stroke work-end-diastolic volume relation. Diastolic compliance was derived from the end-diastolic pressure-volume pressure relation. The results were compared with a control group with no ischemia. There was no significant deterioration in left ventricular systolic contractile functions as demonstrated by the analysis of elastance and the preload recruitable stroke work area in any of the modifications of UW. However, significant deterioration in the diastolic compliance occurred in the UW-E and UW-HS groups. A similar trend was found in the UW-L group, although it was not statistically significant, whereas the diastolic compliance was preserved in the UW-R group. CONCLUSIONS: The intracellular electrolyte composition and the hydroxyethyl starch are important in the preservation of left ventricular diastolic function, whereas the omission of raffinose was inconsequential. The replacement of lactobionate by chloride had less untoward functional effects compared with studies of other solid organ preservation.

Adenosine↗
PubMed1992

Superiority of the University of Wisconsin solution over simple crystalloid for extended heart preservation. A study of left ventricular pressure-volume relationship.

To compare the effects of the University of Wisconsin solution with those of an extracellular crystalloid solution, Krebs-Ringer bicarbonate, as cardiac preservation media, we studied 35 adult dogs in an isolated heart preparation. Four groups of seven hearts were preserved in University of Wisconsin solution for 6 or 12 hours or in Krebs-Ringer bicarbonate solution for 6 or 12 hours. An additional group of seven hearts with no ischemia was used for a control group. In the four preservation groups, hearts were arrested by electrolyte solution (Normosol with potassium chloride, 20 mEq/L, added, 4 degrees C), flushed with 200 ml of the preservation solution, and then stored in the same solution at 1 degree to 2 degrees C. The hearts were mounted on an isolated heart preparation equipped with a computer-controlled servo-pump system that used a mock arterial system to modulate the aortic input impedance presented to the left ventricle. Left ventricular pressure-volume loops were measured on-line for 2 hours of reperfusion with autologous warm oxygenated blood. Elastance was derived from the end-systolic pressure-volume relationship, and diastolic compliance was derived from the end-diastolic pressure-volume relationship. The total left ventricular performance was assessed by the preload recruitable stroke work area, the slope, and its x-intercept, all of which derived from the stroke work (pressure-volume area)-end-diastolic volume relationship. Extended global ischemia had more deleterious effects on the end-diastolic than the end-systolic pressure-volume relationship. In confirmation with other studies, elastance did not accurately reflect the level of ventricular contractile dysfunction because of the significant amount of diastolic dysfunction. The preservation of myocardial systolic and diastolic functions, as demonstrated by the preload recruitable stroke work area and diastolic compliance, was better in the University of Wisconsin solution groups than in the Krebs-Ringer bicarbonate solution groups after 6 and 12 hours of preservation. In addition, 6 hours of preservation with University of Wisconsin solution maintained normal systolic and diastolic functions as compared with those of the control group. Preservation with University of Wisconsin solution prevented any myocardial edema formation; by contrast, this was significantly increased after 12 hours in Krebs-Ringer bicarbonate solution. Groups preserved with University of Wisconsin solution had less reperfusion injury as evidenced by the release of coronary sinus creatine kinase during reperfusion; they also had improved oxygen use during reperfusion.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine↗