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Biomedical subjects

Y Akyurekli

Publications and source records attributed to Y Akyurekli.

At least 19 recordsLinked to original sources
PubMed1991

Therapeutic irradiation over a permanent cardiac pacemaker.

Therapeutic irradiation of fields containing cardiac pacemakers presents a unique problem to pacemaker physicians and radiation oncologists alike. The present case involved a proposed radiation field containing both subclavian pockets. As an alternative solution, the Cordis model 334A implantable pulse generator was irradiated using a backup temporary pacemaker that was kept outside of any significant radiation exposure. A total of 60 Gy was delivered in 30 fractions, with backup temporary pacing and continuous ECG monitoring used for the first 5 fractions. Frequent re-evaluation of pacing and sensing function revealed no changes as a result of irradiation; following radiotherapy, transtelephonic monitoring showed normal pacemaker function for a 4 month follow-up. This represents a useful alternative, particularly for nonmultiprogrammable pacemakers that are made of more radiation-resistant technology.

Aged↗
PubMed1986

Bronchopleural complications of nasogastric feeding tubes.

Enteral alimentation via small soft feeding tubes is becoming more common as the importance of nutrition is recognized in the debilitated patient. The monofilament wire stylets that stiffen these tubes during their insertion may cause potentially lethal bronchopleural complications unless correct insertion techniques are used and the tube's position is carefully checked before starting enteral nutrition.

Aged↗
PubMed1982

Myocardial responses to acute global ischemia and reperfusion.

Effects of 15 to 120 minutes of global myocardial ischemia without coronary occlusion followed by 60 minutes of reperfusion were examined in anesthetized dogs on total coronary bypass. Thirty minutes or less of global ischemia was found to be fully recoverable, while longer periods of ischemia were associated with irreversible damage. Total and regional myocardial flows and myocardial oxygen consumption did not recover in animals subjected to 60 minutes of global ischemia, while hemodynamic dysfunction became apparent only after 90 minutes of global ischemia. These results indicate that global myocardial ischemia, like coronary artery ligation, will produce functional impairment during reperfusion which is dependent on the duration of the insult.

Animals↗
PubMed1980

Effectiveness of intra-aortic balloon counterpulsation on systolic unloading.

The therapeutic benefit of intra-aortic balloon pumping (IABP) is believed to result from the combined action of reducing myocardial demand (systolic unloading) while improving myocardial supply (diastolic augmentation). However, the relative importance of these aspects has not been fully understood. Accordingly, the systolic unloading responses to IABP were studied in 13 dogs on total coronary bypass. By perfusing the coronary circulation from an extracorporeal source at a controlled pressure the authors were able to analyse the systolic unloading responses without diastolic augmentation directly altering coronary flow. The results suggest that IABP is effective only in reducing myocardial demand at normotensive levels; IABP during hypotensive states did not assist the failing heart mechanically by systolic unloading. Therefore the therapeutic action of IABP must result from increases in coronary blood flow by diastolic augmentation.

Animals↗
PubMed1978

Acute cardiac failure: the relation between coronary flow and oxygen consumption.

In an initial study with dog hearts functioning in situ on total coronary bypass, we demonstrated that predetermined levels of reduced cardiac pump function could be achieved by reducing total coronary flow through changes in the perfusing pressure. In subsequent experiments, oxygen values were measured so that changes in myocardial aerobic consumption in response to brief (3 minute) alterations in coronary perfusing pressure could be determined as well. As a result significant linear correlations were found between coronary flow and myocardial oxygen availability (r = 0.98), oxygen extraction (r = 0.49) and oxygen consumption (r = 0.92). These changes in oxygen values paralleled those in cardiac function (stroke work, r = 0.84).

Animals↗
PubMed1977

Causes of death in aortocoronary bypass surgery: experience with 1,000 patients.

Of the first 1,000 consecutive patients in our unit to receive aortocoronary bypass grafts, 108 have died: 32 at operation, 16 in hospital, and 60 late. Of 343 patients who had a normal ventricle, only 1 (0.29%) died at operation, and 2 of the 8 late deaths were noncardiac in cause. Most operative deaths resulted from low cardiac output, and most later deaths were caused by congestive heart failure. A study of the relation of various clinical and operative factors with mortality found that patients with congestive heart failure who underwent valve replacement and bypass grafting had the worst prognosis (73% mortality) while those undergoing bypass grafting with Class III or IV ventricular function (as we define it) and congestive heart failure were next (49% mortality).

Cardiac Output↗
PubMed1977

Myocardial infarction following coronary artery bypass: factors influencing its occurrence.

The authors have undertaken a prospective study on postoperative myocardial infarciton (PMI) following coronary artery bypass (CAB) grafting. PMI was diagnosed from electrocardiographic findings by the criteria of the American Heart Association. From Aug. 1, 1975 to Feb. 27, 1976, 198 patients (177 men, 21 women) underwent CAB. Their ages ranged from 31 to 71 years (mean, 49 yr). Of these patients, 18 (9%) sustained a PMI. A number of factors were analyzed to determine their influence on the occurrence rate of PMI. Preoperative factors wuch as the New York Heart Association classification, measurement of left ventricular function and evaluation of the severity of coronary artery disease were not helpful in predicting a predisposition to PMI. Endarterectomy was the only operative intervention associated with a higher inicidence of PMI (18%). Other factors such as the interval of cardiac anoxia and cardiopulmonary bypass and the number of vessels grafted did not seem to be associated with PMI. Low blood flow (less than 40 ml/min) through the graft could be correlated with the area of infarction in only 5 of 18 patients. Among the operated patients, postoperative ventricular arrhythmia was much more common in patients with PMI. The hospital mortality in this group was 11% (two patients).

Adult↗
PubMed1977

Experience with reoperation following coronary bypass grafting.

Thirty-four of 1152 patients who had undergone aortocoronary bypass grafting underwent reoperation. There were no early or late deaths among these 34 patients. The average time between operations was 14 months. At the initial operation, 88 grafts and 10 internal mammary implants were placed; at reoperation, 56 grafts and 8 internal mammary implants were placed and a left ventricular aneurysm was plicated. Twenty patients underwent reoperation for graft stenosis or occlusion, five because of progression of coronary artery disease, seven because of combined progression disease and graft occlusion and two to correct technical errors. Improvement in the class of angina was 1.1 classes at an average follow-up of 9 months. The authors believe that reoperation for coronary bypass grafting can be performed safely with symptomatic improvement for the patient.

Coronary Artery Bypass↗
PubMed1976

Five years' experience with aortocoronary bypass grafting.

During a 5-year period (Apr. 14, 1970 to Apr. 14, 1975) 930 patients underwent aortocoronary bypass grafting; the procedure was done as an emergency in 141. Of the entire group 3.3% died at operation, 1.6% died in hospital and 5.8% died later; of the patients undergoing emergency grafting 12.1% died at operation and 5.7% died later. From a detailed analysis of the first 600 patients it was found that both operative and late mortality were clearly related to two factors: severe left ventricular dysfunction at the time of operation and inadequate surgical treatment because of insertion of insufficient numbers of grafts or because of poor blood flow through the grafts.

Adult↗
PubMed1976

Triple-vessel coronary artery disease: Effect of revascularization on late survival.

Of the first 600 patients to receive aortocoronary bypass grafts 383 had three diseased vessels, and of them 36 (9%) have died: 20 (5%) in hospital and 16 (4%) late. In 10 of those who died, ventricular function was normal, class I or class II and in the other 26 function was class III or class IV. For all ventricular classes except class IV, improvement in myocardial blood flow with operation was considerably lower than average in those who died. The leading cause of late death was congestive heart failure followed by myocardial infarction, and then by other cardiac complications. Of patients with good (normal, classes I or II) ventricular function, 3.5% died during a mean follow-up period of 27 months; and since, according to published reports, 1% of patients with triple-vessel disease without surgical intervention die each month, the data from this study suggest that survival in this group is improved by 23.5%. This study also shows that in patients with triple-vessel disease and good ventricular function, adequate coronary artery bypass operations (i.e., placement of three grafts or more) improves survival.

Coronary Artery Bypass↗
PubMed1976

Acute cardiac failure: the relation between coronary flow and cardiac function.

To study the effects of acute coronary hypotension on the working dog heart in situ, both coronary arteries were cannulated and perfused with oxygenated blood at controlled pressures (40 to 120 mm Hg). At a perfusion pressure of 120 mm Hg, total coronary artery flow appeared to be sufficient (0.95+/-0.08 ml/min-g) to maintain normal cardiac performance for a 2.5-hour observation period. During incremental decreases in coronary perfusion pressure, significant linear correlations were found between coronary flow and cardiac index (r=0.84), left ventricular maximum dP/dt (r=0.83), stroke index (r=0.82), stroke work (r=0.83) and mean arterial pressure (r=0.62). During simulated shock conditions (systolic arterial pressure, less than 75 mm Hg), relative reductions in coronary flow (-60.9+/-4.0%) paralleled changes seen in cardiac function and persisted for 28+/-4 min.

Animals↗
PubMed1975

Surgery for coronary artery disease and congestive heart failure.

A group of 41 patients presenting primarily with symptoms of congestive heart failure was investigated by coronary arteriography and myocardial revascularization. Of these patients 20 underwent resection of left ventricular aneurysm or left ventricular plication as well as revascularization. Revascularization plus resection of left ventricular aneurysm gives gratifying results, but revascularization in the presence of severe generalized hypokinesis is less satisfactory; however, the improvement in clinical condition in a sufficient number of patients is such that this approach to their management is justified. Accordingly, every patient with coronary artery disease and congestive heart failure should be investigated by angiography. Numerous factors influence the results of revascularization for the relief of congestive heart failure; the most useful as a criterion to aid patient selection is left ventriculography. In this group of 41 patients 66% were helped by myocardial revascularization.

Adult↗