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Biomedical subjects

A S Casale

Publications and source records attributed to A S Casale.

10 recordsLinked to original sources
PubMed1996

Setting of relatively low energy outputs may permit implantation of a nonthoracotomy automatic cardioverter defibrillator system when high energy outputs prove ineffective.

At intraoperative testing of defibrillation thresholds during implantation of internal cardioverter defibrillators, standard step-down approaches of energy outputs are used. If relatively high energy outputs are not successful at defibrillating the heart, the electrodes are frequently reconfigured. When attempting implantation of a nonthoracotomy lead system, high defibrillation thresholds may warrant opening of the chest cavity to place one or more epicardial electrodes. A case is presented where a nonthoracotomy system was able to be implanted using relatively low energy outputs which were reproducibly successful at terminating ventricular fibrillation when higher energy outputs were unsuccessful. Mechanisms for this phenomenon and alternate recommendations for defibrillation testing are presented.

Aged↗
PubMed1992

Surgical treatment of postinfarction ventricular septal defect with aortic stenosis.

A 69-year-old man with an acute postinfarction ventricular septal defect was also found to have aortic stenosis. Successful management required closure of the postinfarction ventricular septal defect and replacement of the stenotic aortic valve. The contribution of aortic stenosis to the cause of the infarction and the postinfarction ventricular septal defect, as well as the implications for surgical management, are discussed.

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PubMed1991

Current indications, risks, and outcome after pericardiectomy.

A retrospective analysis of the records of 60 patients who underwent pericardiectomy over a 10-year period (1980 to 1990) at The Johns Hopkins Hospital was performed. Indications for operation were effusive disease in 24 patients and constriction in 36 patients. Six patients (10%) with pericardial effusion had pain as the primary symptom necessitating intervention. The operative approach for pericardiectomy was median sternotomy in 52 patients (4 patients required cardiopulmonary bypass) and left anterior thoracotomy in 8 patients. Nine patients (5 with constriction and 4 with effusion) with a prior limited pericardial procedure required formal pericardiectomy. The operative mortality rate for pericardial effusion and constriction was 4.2% and 5.6%, respectively. Follow-up (median follow-up, 56.9 +/- 38.2 months) was obtained on 56 patients (93.3%). Actuarial survival at 1 year, 5 years, and 10 years for all patients was 82.1% +/- 5.1%, 71.7% +/- 6.7%, and 59.8% +/- 12.2%, respectively. A Cox proportional hazards regression analysis was performed using 20 clinical variables. A history of malignancy, previous pericardial procedure, and preoperative New York Heart Association class IV were found to be predictors of poor survival. All patients who underwent operation primarily for effusion with associated pain are alive and have improved functional capacity without steroid use. We conclude that pericardiectomy can be performed with low mortality and can result in good long-term survival and improved functional capacity. Patients who are seen primarily with pain refractory to steroid therapy can be relieved of symptoms with operation.

Actuarial Analysis↗
PubMed1990

Routine use of the left internal mammary artery graft in the elderly.

Left internal mammary artery (LIMA) grafts have better long-term patency rates than do saphenous vein grafts and result in improved late survival. The present study was undertaken to assess the results of LIMA grafting in the elderly. From 1980 through 1988, 723 patients 70 years of age or older had isolated coronary artery bypass grafting performed. During the first 5 years, only 11% of the elderly patients received LIMA grafts, whereas 86% having coronary artery bypass grafting since 1985 had LIMA grafts. Since 1986, LIMA use in the elderly has become routine, with 92% of patients receiving internal mammary artery grafts. During the first 5 years, elderly patients had a hospital mortality rate of 9.3%. Since 1985, the hospital mortality rate fell to 5.5%. In addition, the occurrence of major surgical complications was either unchanged or reduced in patients receiving LIMA grafts. Furthermore, late follow-up indicates a significantly improved 4-year survival rate in patients with internal mammary artery grafts compared with those without: 86 +/- 0.02% versus 77 +/- 0.03% (p less than 0.01). Analysis of multiple potential risk factors for early mortality was performed using multiple logistic regression and late survival using the Cox proportional hazards model. Although unmeasured predictor variables may confound retrospective analyses, LIMA grafting appears to be an independent predictor both of improved early and late survival.

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PubMed1989

Immunosuppression after heart transplantation: prednisone and cyclosporine with and without azathioprine.

Fifty-four patients (group I) underwent isolated heart transplantation between July 1983 and January 1987 and were immunosuppressed with oral prednisone and cyclosporine. Twenty-three patients (group II) were transplanted between January 1987 and June 1988 and were immunosuppressed with oral prednisone, azathioprine, and cyclosporine, with lower targeted cyclosporine blood levels. The groups were similar in sex distribution of both donors and recipients. Primary cardiomyopathy was the primary recipient diagnosis in two thirds of patients in both groups. Donor age, graft ischemic time, and length of recipient hospitalization after transplant were similar. There was a trend toward transplantation of older patients in group II, and group II patients were more likely to receive hearts from local donors. Actuarial survival at 24 months was 75% in group I and 92% in group II. Patients who had triple-drug immunosuppression had statistically less early rejection but more early infections that tended to be minor. Hypertension requiring treatment occurred in 63% of group I patients and 62% of group II patients within the first 9 months after transplantation. Elevation of serum creatinine greater than 2.0 mg/dl occurred in 34% of group I patients and 15% of group II patients. A triple-drug immunosuppressive protocol is associated with less early rejection but more early minor infectious episodes. Although the incidence of hypertension is not reduced, there is a trend toward less nephrotoxicity and better survival.

Actuarial Analysis↗
PubMed1984

Progression and resolution of myocardial reflow injury.

The development of and recovery from a severe yet nonlethal myocardial injury following hyperkalemic cardioplegia and prolonged hypothermic global ischemia was examined over 14 days in a rat model of heterotopic intraabdominal cardiac isograft transplantation. Mitochondrial enzymatic markers of myocardial ischemic injury and light microscopic signs of damage were examined. Eighteen hearts were arrested in situ using hyperkalemic cardioplegia and subjected to a mean of 38 min of ischemia at 20 degrees C as transplantation was achieved. No changes in mitochondrial creatine kinase (CKm) activity, mitochondrial malate dehydrogenase (MDHm) activity, their ratio, or morphologic evidence of injury were found during 8 days of reperfusion. In a second group of 66 hearts, the duration of hypothermic cardioplegic ischemia was extended by 120 min before transplantation. Neither unreperfused hearts nor hearts reperfused for only 1 hr demonstrated significant depression of enzyme activities or microscopic evidence of injury. However, after 1 day of reperfusion, CKm and MDHm activities were depressed to 36 and 44% of control levels (P less than 0.05). These activities had returned to control levels by 2 days of reperfusion and remained stable for 12 days thereafter. Light microscopic analysis revealed cellular injury to be maximal at 1 to 2 days of reperfusion with gradual improvement noted over the following 12 days. These observations suggest the existence of a mitochondrial injury following prolonged cardioplegic arrest and hypothermic global ischemia that is maximal after 24 hr of reperfusion but shows evidence of improvement thereafter. These findings justify aggressive support of the poorly functioning heart for the first few days after prolonged global ischemia.

Animals↗
PubMed1984

The mechanism of mannitol in reducing ischemic injury: hyperosmolarity or hydroxyl scavenger?

The effectiveness of postischemic reperfusion with mannitol has been well documented in previous studies. Mannitol, a hyperosmolar agent, is also an effective scavenger of the cytotoxic hydroxyl radical. If mannitol acts solely as a hyperosmolar agent, hyperosmolar reperfusion with its isomer, glucose, should be equally effective. To elucidate the beneficial effect of mannitol, 24 isolated rabbit heart preparations were subjected to 60 min of hypothermic (27 degrees C) cardioplegic arrest and normothermic reperfusion. There were three study groups with eight hearts in each. Group I hearts were reperfused with an unmodified isosmolar solution. Group II hearts were reperfused with a hyperosmolar (350 mOsm/liter) solution containing glucose, and group III hearts had hyperosmolar (350 mOsm/liter) reperfusion with mannitol. Left ventricular function (developed pressure and maximum positive dP/dt) was measured isovolumically before and after ischemia. Coronary flow was measured volumetrically during reperfusion, and myocardial edema formation was determined after 45 min of reperfusion. Reperfusion with mannitol resulted in significant improvement in recovery of developed pressure (77.3 +/- 2.8% of control vs 65.5 +/- 2.9% in group I and 62.6 +/- 2.2% in group II; p less than .05). Mannitol-treated hearts also had significantly greater coronary flow throughout the reperfusion period and significantly less marked myocardial edema formation compared with hearts treated with isosmolar and hyperosmolar glucose. These data confirm the particular usefulness of mannitol in improving postischemic ventricular function, maintaining coronary blood flow during early reflow, and reducing myocardial edema formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Reduction of myocardial ischemic injury with oxygen-derived free radical scavengers.

Experimental data suggesting that oxygen-derived free radicals may play a role in the myocardial injury associated with ischemia and reperfusion are presented. In several studies of prolonged global myocardial ischemia, the administration of free radical scavenging agents, such as superoxide dismutase, catalase, and mannitol, resulted in significantly better recovery of left ventricular function following reperfusion. In a region-at-risk model of localized myocardial ischemia, both superoxide dismutase and allopurinol significantly reduced the extent of myocardial necrosis that developed following reversible coronary arterial branch occlusion. The manner in which oxygen-derived free radicals may be harmful is examined. In particular, the possibility that these toxic species are involved in the exacerbation of the ischemic injury that develops upon reflow and reoxygenation is examined.

Animals↗
PubMedDate not supplied

Twelve-hour cardiopulmonary preservation using donor core cooling, leukocyte depletion, and liposomal superoxide dismutase.

Because leukocytes and oxygen radical species contribute to ischemic and reperfusion injury during organ preservation, we examined the effects of a long-acting liposomal superoxide dismutase (liposomal SOD) and mechanical filtration of leukocytes on cardiopulmonary graft function after 12 hours of static preservation. Bovine heart-lung blocks were harvested, core cooled to 15 degrees C, stored in 4 degrees C donor blood for 12 hours, and then orthotopically transplanted (control group, n = 6). In the leukocyte-depletion group (n = 6), a leukocyte filter was incorporated in the bypass circuits of the donor and recipient. In the SOD group (n = 6), liposomal SOD (5000 U/kg) was administered in the cardioplegic solution, in the prime of the bypass circuits of donor and recipient, and immediately before recipient heart-lung reperfusion. In the combination group (n = 6), both leukocyte depletion (LD) and liposomal SOD were used. Only four of six control animals survived more than 2 hours after weaning from bypass, whereas all LD, SOD, and LD + SOD animals survived to be studied at 6 hours. Pulmonary function was assessed at 6 hours by arterial oxygen tension on 100% inspired oxygen (PO2), pulmonary vascular resistance (PVR), and postmortem wet/dry lung weight ratios. Arterial pO2 values (mm Hg) were as follows: control, 102 +/- 51; LD, 437 +/- 60*; SOD, 278 +/- 83; and LD + SOD, 504 +/- 54* (*p less than 0.05 vs controls). PVR values (dynes . sec . cm5) were as follows: control, 1975 +/- 697; LD, 682 +/- 131*; SOD, 607 +/- 191*; and LD + SOD 367 +/- 87* (*p less than 0.05 vs controls).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗