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Biomedical subjects

H B Barner

Publications and source records attributed to H B Barner.

At least 109 records · Page 6Linked to original sources
PubMed1984

Global left ventricular impairment and myocardial revascularization: determinants of survival.

Of 2,782 patients undergoing isolated coronary artery bypass grafting (CABG) from 1970 through 1979, 196 exhibited severe global impairment of left ventricular (LV) wall motion preoperatively (LV score, greater than or equal to 15; ejection fraction, less than 0.40 in all patients and less than 0.30 in 67%). The initial 89 patients (Group 1) underwent CABG without potassium chloride cardioplegia. The subsequent 107 patients (Group 2) were given potassium chloride cardioplegia intraoperatively. Group B patients received more grafts per patient (3.1 versus 2.5; p less than 0.001) and were completely revascularized more often (72.9% versus 58.4%; p less than 0.05). Operative mortality was lower in Group B (3.7% versus 12.4%; p less than 0.025), and 5-year cumulative survival was better in Group B (88.8% versus 63.9%; p less than 0.0001). Preoperative congestive heart failure resulted in higher operative mortality (14.3% versus 4.5%; p less than 0.05) and lower 5-year survival (65.0% versus 81.8%; p less than 0.02). Complete revascularization led to higher 5-year survival (82.2% versus 66.0%; p less than 0.02) but did not alter operative mortality significantly (6.9% versus 9.1%). Potassium chloride cardioplegia may influence operative survival favorably by reducing perioperative myocardial infarction in patients with severe LV dysfunction. Long-term survival relates to completeness of revascularization and severity of congestive heart failure as variables independent of methods of myocardial protection.

Coronary Artery Bypass↗
PubMed1984

Pathomorphologic aspects of muscular tissue in diabetes mellitus.

Biopsy specimens from the myocardium were examined in a series of 145 patients who had elected coronary arterial bypass grafting. The patients were divided into three groups; 1) overtly diabetic (OD) patients; 2) chemically diabetic (CD) patients, who demonstrated impaired glucose tolerance only when stressed with a sugar load; and 3) normoglycemic, nondiabetic (ND) patients, who served as a control group. Tissue plugs from the left anterior apical segment of the heart and from the quadriceps femoris in 71 patients, for comparative evaluation, were prepared for ultrastructural examination. Findings were as follows: 1) Myocardial hypertrophy and interstitial fibrosis were twin characteristic abnormalities, seen in all but two of the biopsy specimens; capillary endothelial changes, the third most common abnormality, were present in approximately half of these specimens, regardless of the patients' metabolic status. 2) In patients matched by sex, age, weight, blood pressure, preoperative myocardial ventricular function, and coronary arterial integrity, capillary basal laminar thickening represented a pathomorphologic hallmark, distinguishing structural alterations in the diabetic from those in the normoglycemic patient. 3) Although clear-cut and statistically significant thickening of basal laminae was noticeable in OD patients, a) in the quadriceps markedly increased laminar thickening was present in a number of ND patients, rendering interpretation of this change in skeletal muscle as pathognomonic for diabetes doubtful; and b) within cardiac muscle this increase in laminar width was less than that seen in skeletal muscle, leaving the functional implications of this alteration in doubt. 4) Early but statistically significant increases in capillary basal laminar thickening were observed in the myocardium of CD patients; these patients demonstrated impaired glucose tolerance only when stressed with a sugar load, without exhibiting overt diabetic manifestations. 5) In this group of highly selected patients with epicardial coronary arterial disease, the histopathologic profile of the diabetic myocardium did not include distinctive abnormalities sufficient to warrant the designation of "diabetic cardiomyopathy," indicating that coronary arterial bypass grafting can be recommended for the diabetic patient who requires this procedure.

Adult↗
PubMed1984

Effect of intraoperative propranolol on serum creatine kinase MB release in patients having elective cardiac operations.

Intraoperative beta blockade has been evaluated as an adjunct to hypothermic cold blood potassium cardioplegia by quantitating serum creatine kinase MB release. Randomization of 80 patients having coronary artery bypass grafting and 18 patients having valve replacement with or without bypass grafting resulted in 46 of the former and seven of the latter receiving propranolol 0.05 mg/kg 4 to 5 minutes before aortic cross-clamping. Among patients having bypass grafting, infarct size (in gram-equivalents) was 7.9 +/- 0.7 gm-Eq for the propranolol group and 10.3 +/- 0.8 (p less than 0.05) for the control group. Ischemic times were 71.6 +/- 2.8 and 78.3 +/- 3/4 minutes (p = NS), respectively. In valve replacement, infarct size was 9.9 +/- 1.9 gm-Eq for those receiving propranolol and 12.6 +/- 2.0 (p = NS) for the control subjects; ischemic times were 99.4 +/- 12.5 and 80.5 +/- 5.7 minutes, respectively. When the two groups receiving propranolol were combined, infarct size was 8.2 +/- 0.6 gm-Eq versus 10.9 +/- 0.7 (p less than 0.01). When ischemic time was plotted against infarct size, analysis by linear regression revealed a significant correlation for patients receiving propranolol and having bypass grafting (p less than 0.01) and for all patients receiving propranolol (p less than 0.01). These data demonstrate a modest reduction of infarct size with intraoperative propranolol as an adjunct to our standard management of patients having aortic cross-clamping. Quantitation of creatine kinase MB release is the best clinically available method for assessing alterations in techniques of myocardial preservation.

Coronary Artery Bypass↗
PubMed1984

Cold blood potassium diltiazem cardioplegia.

Despite the use of cold blood potassium (CBK) cardioplegia, the severely impaired myocardium and/or long ischemia time continue to be a challenge. Because of the association of Ca++ with cell injury and death, the use of Ca++ entry blockers is logical. Investigation of cold blood diltiazem (CBD) revealed no advantages over CBK cardioplegia. The combination of potassium and diltiazem is appropriate because of their different mechanisms of action. Ten dogs had 1 hour of myocardial ischemia with topical ice (temperature 7 degrees +/- 2 degrees C) after coronary perfusion with 200 ml of cold blood (5 degrees +/- 1 degree C) containing potassium (30 mEq/L) and diltiazem (400 micrograms/kg). Eight dogs had 2 hours of ischemia after perfusion with 200 ml of cold blood containing potassium (30 mEq/L) and diltiazem (200 micrograms/kg) and reperfusion every 30 minutes with 100 ml of cold blood containing KCl (30 mEq/L) and diltiazem (100 micrograms/kg). Six dogs received the same treatment as the previous group except that diltiazem was increased to 1,600 micrograms/kg for all four perfusions. Baseline studies were repeated after 60 minutes of reperfusion without the use of Ca++ or inotropic agents. Heart rate, peak systolic pressure, velocity of the contractile element (Vce), maximum velocity of contractile element (Vmax), peak +dp/dt, peak -dp/dt, dp/dt over common peak isovolumic pressure, left ventricular compliance, stiffness and elasticity, and heart water were unchanged from control. Coronary vascular resistance was unchanged in Groups 1 and 2 but declined in Group 3. Creatine phosphate was preserved during ischemia; adenosine triphosphate (ATP) declined. With reperfusion there was continued fall in ATP, ADP, and the adenosine pool. Ultrastructure was well preserved. In 16 of 24 dogs defibrillation was not required, whereas all 48 dogs with CBK and all 13 with CBD required defibrillation. These data suggest that the addition of diltiazem to CBK provides more effective cardioplegia (preservation of creatine phosphate), although ATP and the adenosine pool continued to decline with reperfusion.

Adenosine Triphosphate↗
PubMed1983

The left internal mammary artery as a sequential graft to the left anterior descending system.

The left internal mammary artery (IMA) has been used as a sequential graft to the left anterior descending (LAD) system in 39 patients. Seven patients having operation in 1977 were followed up for 2 years, and cardiac catheterization in four revealed no problems related to the anastomoses. After a 2 year hiatus we resumed use of the procedure in 1980. A total of 10 patients have had catheterization from 1 month to 5 years postoperatively with no anastomotic narrowing or restriction of distal IMA flow by the side-to-side anastomosis. The IMA should be equal to or greater in size than the larger of the two vessels to be grafted. We continue to use this procedure in carefully selected patients.

Adult↗
PubMed1982

Coronary artery stenosis following aortic valve replacement and intermittent intracoronary cardioplegia.

From July, 1977, to July, 1980, intermittent cold blood potassium cardioplegia was used in 208 patients undergoing aortic valve replacement. Aortic root injection of the cardioplegic solution at 10 degrees C was followed every 20 to 30 minutes by infusions of the solution through Silastic cannulas sutured in the coronary orifices or reinserted with each injection. Symptoms of myocardial ischemia developed in 6 patients 3 to 30 months postoperatively. Coronary angiography confirmed new stenoses of the left orifice (3 patients), left main trunk (1 patient), left anterior descending coronary artery (2 patients), circumflex coronary artery (1 patients), and right orifice (3 patients). Four patients underwent saphenous vein grafting procedures, with 2 deaths; 2 patients refused reoperation. A seventh patient with 80% stenosis of the circumflex coronary artery and a posterolateral myocardial infarction died 2 months after double-valve replacement. Intermittent cold blood potassium cardioplegia instead of continuous perfusion did not prevent coronary arterial injury. Injuries occurred in the distal coronary arteries as well as the orifices and were not prevented by withdrawal of the cannulas between injections. Tight-fitting cannulas and high-pressure injection should be avoided. A careful search for coronary arterial injury should be made in all symptomatic patients following aortic valve replacement.

Adult↗
PubMed1982

Late patency of the internal mammary artery as a coronary bypass conduit.

From January, 1972, through August, 1977, 472 patients had internal mammary artery (IMA) coronary bypass, of which 100 were double-IMA bypasses. We selected those patients having a widely patent IMA one year postoperatively who then had a second catheterization 49 to 105 (mean, 64) months following operation. None of the 93 patients who met these criteria was specifically recalled for this study; they all had follow-up catheterizations for multiple other reasons. All of the 91 left IMA and 22 right IMA bypasses (total, 113) were patent at late catheterization, but 1 right IMA was diffusely narrowed. One left IMA had acute angulation with 50% stenosis proximal to the distal anastomosis, which was unchanged over the follow-up interval. There were 100 patent saphenous vein bypasses at one year and 87 at late catheterization. Late closure of coronary bypass grafts is secondary to progression of coronary disease, atherosclerosis of the bypass conduit, or intimal proliferation. Because we have not encountered the latter two causes of conduit closure, IMA grafts remain our graft of choice for nonemergent operations in patients under 60 years of age having revascularization of the left anterior descending coronary artery system.

Arteriosclerosis↗
PubMed1982

Cold blood-diltiazem cardioplegia.

The calcium channel blocker, diltiazem, has been studied in the same model used for evaluation of cold blood-potassium cardioplegia. Six dogs (Group 1) had one hour of myocardial ischemia with topical ice (myocardial temperature, 7 degrees +/- 2 degrees C) after coronary perfusion with 200 ml of cold blood (5 degrees +/- 1 degree C) containing diltiazem, 400 micrograms per kilogram of body weight. Seven dogs (Group 2) had two hours of ischemia after perfusion with 200 ml of cold blood containing 200 micrograms/kg and reperfusion every 30 minutes with 100 ml of cold blood and diltiazem, 100 micrograms/kg. Baseline studies were repeated after rewarming and 40 minutes of reperfusion. No inotropic agents or calcium were used. Heart rate, peak systolic pressure, velocity of the contractile element, peak + rate of rise of left ventricular pressure (dP/dt), peak - dP/dt, dP/dt over common peak isovolumic pressure, left ventricular compliance and stiffness, and heart water were unchanged in Group 1. In Group 2, heart rate slowed (p less than 0.025) and compliance decreased (p less than 0.02). In both groups, coronary vascular resistance declined (p less than 0.001) and recovery of adenosine triphosphate (p less than 0.001), adenosine diphosphate (p less than 0.025), and the adenosine pool (p less than 0.001) was impaired. Ultrastructure was well preserved, but myofibrillar lesions were noted in Group 2. Diltiazem cardioplegia was associated with good functional recovery, but there was impairment of high-energy phosphate metabolism.

Adenosine↗
PubMed1982

Quadriceps and myocardial capillary basal laminae. Their comparison in diabetic patients.

Quadriceps and myocardial biopsy specimens were obtained from 24 patients undergoing elective coronary arterial bypass grafting. Patients were divided into those with chemical diabetes (CD) (with incidentally discovered elevated glucose levels when stressed), overt diabetes (OD) (who required insulin support), and euglycemic nondiabetics (ND). Specimens from the quadriceps femoris and left anterior apical segment of the heart were examined ultrastructurally, with particular attention to the evaluation of capillary basal laminar thickness, using morphometric techniques. Results indicate (1) an increased, though statistically insignificant, thickening of capillary basal laminae in the quadriceps of CD and OD patients, in contrast with statistically significant laminar thickening in the diabetic myocardium; (2) early, mild laminar thickening in quadriceps and myocardium of the asymptomatic CD group; and (3) two characteristic patterns of basal laminar contours, homogeneous and lamellated, the latter being seen prominently in the quadriceps of diabetic patients in frequent association with pericapillary edema. These findings support the concept that basal laminar thickening in the diabetic is associated with deranged carbohydrate metabolism.

Adult↗
PubMed1981

Traumatic occlusion in fibromuscular dysplasia of the carotid artery.

A patient with fibromuscular dysplasia involving the cervical carotid artery developed subtotal occlusion after a trivial head injury. An association between occlusion in fibromuscular dysplasia-diseased carotid arteries and trivial blunt head injuries is suggested and appropriate treatment options are discussed.

Arterial Occlusive Diseases↗
PubMed1981

Continuous hydralazine infusion for afterload reduction.

Impedance reduction with a continuous infusion of hydralazine was evaluated in 20 patients following cardiopulmonary bypass. Patients were selected for therapy when the cardiac index (CI) was less than 2.2 L/m2/min, when the systemic vascular resistance index (SVRI) was greater than 2,500 dyne sec cm-5, or when both conditions were present. No other vasoactive or cardiotonic drugs were used intraoperatively or postoperatively. Responses were measured at 15, 30, 60, 120, 180, and 240 minutes and compared with control measurements. Significant responses appeared by 15 minutes in the mean arterial pressure, CI, and SVRI, which were maximal by 2 hours. At 4 hours, the SVRI was 1,520 +/- 276 dyne sec cm-5 (control, 3,235 +/- 222) and pulmonary vascular resistance index, 365 +/- 102 dyne sec cm-5 (control, 592 +/- 71). The CI was 3.20 +/- 0.29 L/m2/min (control, 1.96 +/- 0.16) and mean arterial pressure, 75 +/- 2.3 mm Hg (control, 92 +/- 2.4). Left atrial, pulmonary artery diastolic, and right atrial pressures increased from control but not significantly: 11.4 +/- 0.8 to 13.3 +/- 1.2 mm Hg, 13.6 +/- 1.6 to 17.2 +/- 1.5 mm Hg, and 6 +/- 1.6 to 9.4 +/- 1.7 mm Hg, respectively. In 16 patients, hydralazine was continued for 24 hours and in 11, the transition to oral therapy was made. Hydralazine by infusion effectively reduces after load, avoids the fluctuations of bolus therapy, and allows the transition to oral therapy if needed.

Blood Pressure↗
PubMed1981

Left main equivalent: results of medical and surgical therapy.

Stenosis of at least 50% of both the left anterior descending and circumflex coronary arteries proximal to their major branches has sometimes been called left main equivalent (LME) disease. During a 4-year interval, 189 LME patients were identified as surgical candidates by angiographic criteria. Coronary artery bypass grafting (CABG) was performed in 119 patients; 70 patients were managed nonoperatively. Treatment assignment was nonrandom. During the same interval, 203 patients with significant left main coronary artery (LMCA) stenosis and 742 patients with three-vessel disease without LMCA or LME stenosis underwent CABG. Follow-up is 99.2% complete at an average of 48 months (range 24--73 months). Operative mortality was significantly higher among LMCA patients (4.0%) than among LME surgical patients (0.8%) (p less than 0.05). Cumulative 5-year survival was better among LME surgical patients (98.2 +/- 1.3%) than among LME medical patients (75.9 +/- 5.7%) (p less than 0.0001) or LMCA surgical patients (92.8 +/- 2.1%) (p less than 0.03). All operative patient groups had a significantly lower incidence of myocardial infarction (10.3--13.4%) than the LME medical patients (25.7%) (p less than 0.05). Relief of angina was also significantly better in the operative groups (61--67.6%) than in LME medical patients (36%) (p less than 0.005). Major differences exist between LME and LMCA patients; LME is more properly considered a variant of multivessel coronary artery disease. Results of medical and surgical therapy suggest that patients with LME disease should be strongly considered for early operative therapy.

Aged↗