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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Type I dissecting aortic aneurysm is not only the most common type of all but an extremely lethal event. It is important to create the experimental model of type I dissection for clarifying behavior of this disease and successful treatment. The purpose of this study is: (1) production of experimental model of type I aortic dissection; (2) examination of progression manner of dissection; (3) and investigation of influence of dissection upon aortic valve and coronary artery. The experimental model of type I aortic dissection was produced in adult mongrel dogs. Bilateral thoracotomy was made and intimal tear was created in the ascending aorta by modified Blanton's procedure. Hypertension and creation of large pocket of the aortic media were necessary to produce type I aortic dissection. Extension of dissection had a tendency toward the inner layer of the aortic wall at distal site. However, at proximal site the dissection progressed in the same layer of the aortic wall. In this series, retrograde extension of dissection remained blind above annulus of aortic valve, and no incidence of aortic regurgitation or coronary ischemia was occurred. But on histologic examination, degeneration of the aortic wall by the dissection was observed. Such weakness of aortic wall showed potentiality to developed into subsequent aortic regurgitation or coronary ischemia.
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PMID:[Experimental study on the dissecting aortic aneurysm]. 260 44

Asymmetric septal hypertrophy is considered by many to be pathologic but its presence in a number of states associated with left ventricular overload indicates that it may develop as an adaptive feature in the overloaded heart. This hypothesis implies that initially in these states a greater systolic stress and thus energy metabolism occurs in the ventricular septum than in the left ventricular free wall. It was previously demonstrated that in the early stages of ischemia regional differences in energy metabolism could be determined by comparisons of tissue high energy phosphate depletion and lactate accumulation. In the present study these measurements were made in an animal model of left ventricular overload. In open chest dogs aortic insufficiency was produced, which served to provide both volume overload to the left ventricle and regional myocardial ischemia. In addition to regional metabolite levels, measurements of regional blood flow were determined using radioactive microspheres. Tissue samples were taken from the left ventricle and interventricular septum, freeze clamped, divided transmurally into thirds and analyzed for creatine phosphate, adenosine triphosphate and lactate. Animals with myocardial ischemia after aortic insufficiency were classified into two groups: those in which ischemia was limited to the inner left ventricle and left side of the septum and those with more extensive ischemia transmurally. In the latter group, creatine phosphate depletion and lactate accumulation were greater in the septum, but myocardial blood flow was also more depressed in the septum than in the left ventricle. In the former group, where ischemia was more restricted, metabolite changes were also more severe in the left septum than in the inner left ventricle.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Regional blood flow and metabolite levels in the left ventricular free wall and septum during aortic insufficiency: implications for the development of asymmetric septal hypertrophy. 294 41

As a result of improvement in intraoperative and postoperative management, severe aortic valve disease can be cured by operation, however, late cardiogenic sudden death after aortic valve replacement (AVR) has been existed as one of the important unsolved problem. This report is aimed to predict the risk factors influencing the postoperative prognosis of severe aortic valve disease. Twenty-three cases with aortic regurgitation (AR) and 20 cases with aortic stenosis (AS) were selected by postoperative period over 12 months. In 18 AR cases with normal coronary artery substantiated by selective coronary angiography, cross sectional area index of left ventricular wall (CSAI) and ST depression in left chest leads of electrocardiogram correlated well as the CSAI increased, so decreased the ST segment. This shows the increment of CSAI leads left ventricular endocardial ischemia. By means of introduction of this indicator, 23 AR and 20 AS patients were divided into two groups as group C-I having CSAI over 20 cm2/m2 and group C-II under 20 cm2/m2. Left ventricular ejection fraction (EF) was selected as an predictive indicator of left ventricular function. As same as CSAI, AVR cases were divided into two groups as group E-I having EF under 50% and E-II over 50%. Each group was compared concerning with the complication rate of postoperative low cardiac output syndrome (LOS) and late cardiogenic sudden death. In C-I group of AR, 55% cases accompanied with LOS, 18% died due to LOS and 18% died suddenly from late cardiogenic cause, however, none of cases in C-II group had these complications.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Risk factors influencing the prognosis of severe aortic valve disease following aortic valve replacement]. 369 58

Angina occurring in patients with Takayasu's aortitis is attributed to the narrowing of the coronary ostium and/or aortic regurgitation. We treated a patient with Takayasu's aortitis with effort angina, in whom there was no obstruction of the ostium or aortic regurgitation. Treadmill exercise stress test revealed significant ST depression in leads V4-6, II, III and aVF with chest pain. Examinations of lactate in coronary sinus as well as arterial blood suggested the occurrence of myocardial ischemia during atrial pacing. The DPTI/TTI index was decreased and the left ventricular end-diastolic pressure was increased during angina. It is considered that the reduced coronary perfusion pressure resulted from a low diastolic aortic pressure and the elevated left ventricular end-diastolic pressure decreased the DPTI/TTI index and contributed to the development of subendocardial ischemia.
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PMID:Effort angina without coronary obstruction in a patient with Takayasu's aortitis: a case report. 389 49

A rate-related change in ST-segment depression with exercise (ST/HR slope) of 6.0 microV/beat/min or more has been proposed as an accurate predictor of 3-vessel coronary artery disease (CAD). To further assess the accuracy and functional correlates of this method, exercise electrocardiograms were compared with radionuclide rest and exercise left ventricular (LV) ejection fraction (EF) and angiography in 35 patients with stable angina. The ST/HR slope was significantly increased in patients with 3-vessel CAD. An ST/HR slope of 6.0 or more identified 3-vessel CAD with a sensitivity of 89% and specificity of 88%. The predictive value for 3-vessel CAD was 73% owing to the presence of 3 false-positive slopes. The patients from whom these slopes were derived had functionally severe 2-vessel CAD, with an average decrease in exercise LVEF of 13%. Two of these 3 had additional left main CAD and the third has unsuspected additional aortic regurgitation. For the entire group, the exercise ST/HR slope was linearly related to the exercise change in LVEF (r = -0.55, p less than 0.001). Mean exercise change in LVEF for stable angina patients with ST/HR slopes of 4.5 or more was significantly different from that for patients with lower ST/HR slopes (-12 +/- 1% vs + 2 +/- 2%, p less than 0.0001). Thus, the ST/HR slope is both sensitive and specific for the identification of 3-vessel CAD, and high ST/HR slopes in patients with less extensive anatomic disease may predict functionally severe ischemia.
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PMID:Correlation of the exercise ST/HR slope with anatomic and radionuclide cineangiographic findings in stable angina pectoris. 403 22

A 20 year (1963 to 1982) surgical experience including 175 consecutive patients with aortic dissections was analyzed by logistic discriminant analyses to identify predictors of high operative risk. The patient population had characteristics similar to those in large autopsy series. Sixty-nine percent had type A and 58% had acute dissections. The intimal tear was located in the ascending aorta in 60% of the patients, the descending aorta in 27%, and the transverse arch in 13%. The overall operative mortality rate was 23 +/- 3%. The operative mortality rates were substantially lower between 1977 and 1982: mortality in patients with acute type A dissections, 7 +/- 5%; in those with chronic type A, 11 +/- 7%; in those with acute type B, 13 +/- 12%; and in those with chronic type B, 11 +/- 11%. After preliminary univariate screening, the following factors were determined to be significant independent predictors of operative mortality (in rank order of declining predictive power): type A patients (n = 121), renal dysfunction, tamponade, renal/visceral ischemia, and operative date; type B patients (n = 54), rupture, renal/visceral ischemia, and age; all patients (n = 175), renal dysfunction, renal/visceral ischemia, site of tear (ascending less than descending less than arch), tamponade, operative date, and pulmonary disease. Interestingly, several variables had no important bearing on operative mortality, including type (acute vs chronic) of dissection, age, previous operation, rupture, stroke, paraplegia, Marfan's syndrome, concomitant aortic valve replacement and/or coronary artery bypass grafting, site of tear, and whether or not the tear was resected in type A patients; emergency operation, hypertension, previous cardiac symptoms, paraplegia, site of tear, and resection of tear in type B patients; and, when all patients were considered together, age, sex, cardiac symptoms, prior operation, stroke, paraplegia, acute myocardial infarction, acute aortic regurgitation, Marfan's syndrome, and tear resection. These data allow calculation of any individual patient's operative risk and document that the operative mortality rate today is relatively low for all patients with aortic dissections, irrespective of type or acuity. Earlier surgical referral of patients with acute type A or acute type B dissection before irreversible major end-organ ischemia and/or infarction is probably in part responsible for the substantially improved results since 1977.
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PMID:Independent determinants of operative mortality for patients with aortic dissections. 623 61

Presently we favor heparinless femorofemoral venoarterial bypass for all descending thoracic aneurysm resections. The advantages are minimal blood loss due to the absence of heparin, ease of insertion, especially in large aneurysms where it would be difficult to insert a temporary shunt, distal aortic perfusion, possibly a safety factor in preventing spinal cord and visceral ischemia, and prevention of left heart overload and myocardial failure. In acute traumatic ruptures, simple aortic cross clamping is a suitable alternative. It is safe and can be carried out expeditiously in any community hospital where bypass facilities may not be available. Proximal hypertension can be controlled pharmacologically. We have also used this successfully in ruptured atherosclerotic aneurysms. We have no experience with temporary tridodecylmethylamonium (TDMAC) shunts; several groups have used them successfully. We believe they may be difficult to insert in the proximal aorta with a large mediastinal hematoma or extensive aneurysm. Cannulation of the left ventricular apex necessitates cardiac manipulation and may produce effective aortic valve insufficiency. In patients with aortoesophageal and bronchoesophageal fistula, permanent extrathoracic bypass is preferable to a prosthetic graft in a contaminated field. We propose using a permanent bypass with a no. 10 or 12 right axillofemoral bypass. Our experience is limited to only two patients. This is also a method of treating a mycotic aneurysm or infected thoracic aortic graft.
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PMID:Descending thoracic aortic aneurysm: a 10 year surgical experience. 697 87

This report describes deep, non-infarctional T wave inversions occurring after aortic valve replacement for severe, chronic aortic regurgitation. These new T wave inversions may reflect the effect of abruptly converting a severe preoperative diastolic overload state to a post-operative systolic overload state caused by mild or moderate prosthetic valve stenosis. Other factors such as non-infarctional intra-operative ischemia or mechanical injury may also play a role in the pathogenesis of these repolarization abnormalities. The T wave changes were most marked in the immediate post-operative period and tended to regress in the weeks and months following value replacement. The differential diagnosis of these ST-T changes is discussed.
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PMID:Deep T wave inversions after value replacement for chronic aortic regurgitation: possible conversion from a diastolic to systolic overload pattern. 743 Aug 68

From January 1991 to October 1994, 20 Ross procedures were performed. Mean age was 39.70 +/- 7.72 years, range 26 to 56 years. Male/female ratio was 14/6. Nineteen operations were elective, one was semiurgent. Predominant valvular lesion was stenosis in seven patients, aortic regurgitation in four, mixed disease in eight and prosthetic dysfunction in one patient. Twelve pulmonary autografts were implanted in the subcoronary (SC) position, eight as an intraaortic cylinder (inclusion technique (INCL)). Early mortality (< 30 days postoperative) was one (5.0%), there was no late mortality. Reoperation for valve failure occurred in two patients (10.0%). Additional CABG was performed in two patients (10.0%) for technical reasons. Major ECG changes were detected in five patients (three RBBB, two ischemia). No thromboembolic events were reported. Mean follow up was 21.2 months. Aortic insufficiency (AI) at one year was similar in the SC and INCL group. AI grade I in SC: 60%, in INCL: 60%; AI grade II in SC 10%, in INCL: 20%. At two years AI grade I occurred in 100% of the SC group. At three years AI grade I occurred in 75% of the SC group and AI grade II in 25%. No patients of the INCL group had two- or three-year follow up. At discharge slight pulmonary regurgitation was traced in only three patients and it remained stable during the follow up.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Three years surgical and clinical experience with the Ross procedure in adults. 758 50

The relative contributions of left ventricular structural changes, dysfunction, and subendocardial ischemia in determining electrocardiographic repolarization abnormalities were assessed in 53 patients with chronic, pure aortic regurgitation and no evidence of coronary artery disease. Thirty-six patients with an abnormal electrocardiographic pattern of repolarization showed larger end-diastolic (154 +/- 46 vs 120 +/- 32 mL/m2; P < .001) and end-systolic (80 +/- 40 vs 52 +/- 30 mL/m2; P = .016) volumes, higher end-diastolic pressure (22 +/- 11 vs 15 +/- 10 mmHg; P = .021), lower ejection fraction (52 +/- 12 vs 59 +/- 13%; P < .05) and greater mass (168 +/- 48 vs 140 +/- 44 g/m2; P < .05) of the left ventricle compared to 17 patients with normal repolarization. Furthermore, patients with repolarization abnormalities also showed higher peak meridian (217 +/- 68 vs 153 +/- 92 Kdyne/cm2; P < .001) and circumferential (358 +/- 110 vs 259 +/- 153 Kdyne/cm2; P < .001) stress and a more spherical shape (end-diastolic shape: 1.4 +/- 0.1 vs 1.5 +/- 0.2, P = .046; end-systolic shape: 1.7 +/- 0.3 vs 1.9 +/- 0.3, P = .026) of the left ventricle. Patients with secondary repolarization abnormalities were also older than patients with normal repolarization (56 +/- 10 vs 40 +/- 11 years; P < .001). However, the diastolic pressure-time index/systolic pressure-time index, which is an estimate of the myocardial oxygen supply-to-demand ratio, was similar in both groups of patients (0.74 +/- 0.3 vs 0.8 +/- 0.2; P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Relation between ECG strain pattern and left ventricular morphology, left ventricular function, and DPTI/SPTI ratio in patients with aortic regurgitation. 793 Sep 80


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