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Biomedical subjects

R K Myler

Publications and source records attributed to R K Myler.

At least 37 records · Page 2Linked to original sources
PubMed1991

Causes and correlates of death after unsupported coronary angioplasty: implications for use of angioplasty and advanced support techniques in high-risk settings.

To better understand the factors predisposing a patient to death after elective percutaneous transluminal coronary angioplasty (PTCA) and to gain insight into indications for high-risk PTCA both with and without adjunctive use of support devices, the outcomes of 8,052 consecutive procedures were reviewed. Death occurred after 32 procedures (0.4%) and was directly related to coronary artery closure in 26 (81%) of these cases. Left ventricular failure due to vessel closure at the dilated site, the most common cause of death, was independently correlated with female sex (p less than 0.001), "jeopardy score" (p less than 0.001) and PTCA of a proximal right coronary artery site (p = 0.002), but not with left ventricular ejection fraction or presence of multivessel disease. Right ventricular failure after closure of the proximal right coronary artery, and left main coronary dissection accounted for the majority of the remaining deaths. Systolic blood pressure immediately after coronary artery closure was also closely correlated with jeopardy score, and cardiogenic shock was frequent in women with scores greater than or equal to 3.5 and in men with scores greater than or equal to 5.0. These data highlight the superiority of the jeopardy score versus ejection fraction in the determination of risk, stress the importance of gender in determining outcome and point to the need for better means of right ventricular protection from severe ischemia. Therefore, an initial framework for rational use of PTCA and support devices in the high-risk setting is established.

Aged↗
PubMed1991

Silent ischemia after coronary angioplasty: evaluation of restenosis and extent of ischemia in asymptomatic patients by tomographic thallium-201 exercise imaging and comparison with symptomatic patients.

One hundred sixteen patients were evaluated to determine the ability of single photon emission computed tomographic (SPECT) thallium-201 exercise and redistribution imaging to detect silent ischemia secondary to restenosis in asymptomatic patients after single and multiple vessel percutaneous transluminal coronary angioplasty and the findings were compared with SPECT imaging detection of restenosis in symptomatic patients. The value of exercise electrocardiography (ECG) and the amount of ischemic myocardium in symptomatic and asymptomatic patients were determined. Forty-one patients were asymptomatic after angioplasty; 77% of these had chest pain before angioplasty. Seventy-five patients had chest pain after angioplasty; 99% of these had chest pain before angioplasty. Restenosis occurred in 61% of asymptomatic and 59% of symptomatic patients and in 46% of the vessels in both asymptomatic and symptomatic patients. Sensitivity, specificity and accuracy for detection of restenosis by SPECT in individual patients were 96%, 75% and 88% versus 91%, 77% and 85%, respectively, in the asymptomatic versus symptomatic groups (p = NS). Sensitivity, specificity and accuracy for restenosis detection in individual vessels were 90%, 89% and 89% versus 84%, 77% and 84%, respectively, in the asymptomatic and symptomatic groups (p = NS), with similar results for the three major arteries. Sensitivity and accuracy of exercise ECG were significantly less than those of SPECT imaging for the patients with silent (40% and 44%) and symptomatic (59% and 64%) ischemia (p less than 0.001). Restenosis of vessels in the patients with silent and symptomatic ischemia was associated with an equal amount and degree of severity of ischemic myocardium in the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Coronary angioplasty in octogenarians: comparisons to coronary bypass surgery.

Coronary angioplasty was performed in 74 patients 80 years of age and older (mean 83 +/- 3). Single vessel coronary disease was present in 34% and multivessel coronary disease in 66%. Angioplasty of a single vessel was performed in 51 patients (69%), while 23 (31%) had angioplasty of multiple vessels. Angioplasty was successful in 59 of 74 patients (80%). Angioplasty was unsuccessful but uncomplicated in 12 (16%) due to (unyielding) calcified lesions or (impassable) old occlusions. Of these 12, 8 were discharged on medical therapy and 4 underwent elective uncomplicated bypass surgery prior to discharge. Three (4%) patients required emergency coronary bypass surgery due to abrupt vessel closure during the angioplasty procedure, with one hospital death (1.4%). Follow-up (mean 24 +/- 22 months) was obtained in all patients. Of the 59 successful angioplasty patients, late mortality was 10% (cardiac 7% and non-cardiac 3%). Survival and survival without myocardial infarction were both 90%; survival without either infarction or bypass surgery was 86%. Actuarial 3-year survival was 91% and 3-year freedom from death, infarction or bypass surgery was 87% by life-table analysis. Repeat angioplasty for restenosis was performed in 7 patients (12%) without complications.

Actuarial Analysis↗
PubMed1991

Short and long term outcome of percutaneous transluminal coronary angioplasty in unstable versus stable angina pectoris: a report of the 1985-1986 NHLBI PTCA Registry.

In a cohort of 1,720 consecutive patients from the National Heart, Lung, and Blood Institute, Percutaneous Transluminal Coronary Angioplasty (PTCA) Registry (August 1985-May 1986), we compared 768 patients (45%) with stable angina and 952 patients (55%) with unstable angina pectoris. Unstable angina patients exhibited at least one of the following characteristics: new onset angina, rapidly progressing angina, angina at rest, angina refractory to medication, variant angina, acute coronary insufficiency, or angina recurring shortly after an acute myocardial infarct. The distribution of single- and multi-vessel disease was similar among stable and unstable angina patients; multi-vessel disease predominated. Average severity of stenosis and incidence of tubular and diffuse stenosis morphology were higher among patients with unstable angina (both p less than 0.001). Patient success rates were similar in stable and unstable patients. However, on a per lesion basis, overall angiographic success rate and average reduction of severity of stenosis in successfully dilated lesions were significantly higher among patients with unstable angina (both p less than 0.001). Incidence of major patient complications (p less than 0.01) and of emergency coronary bypass surgery (p less than 0.05) were also higher in patients with unstable angina but consistent with their more precarious clinical condition and stenosis morphology. During a two year follow-up, the cumulative distributions of death, myocardial infarct, repeat PTCA, and coronary bypass surgery were not significantly different in patients with stable angina compared to patients with unstable angina. Comparison of the current PTCA Registry cohort with the cases reported in the 1979-1982 Registry revealed a 19% higher success rate for both stable and unstable angina patients. Major complication rates decreased between time periods for stable but not for unstable angina patients. Incidence of emergency bypass surgery decreased more for stable than for unstable angina patients. Coronary angioplasty is indicated in properly selected patients with unstable angina and both single- and multi-vessel coronary disease.

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PubMed1991

Brachial rotational atherectomy.

The brachial approach adds a new dimension to rotational atherectomy. The two cases presented included a large ectopic right coronary artery and a right internal mammary graft where both outcomes were successful. These cases demonstrate that the brachial approach can facilitate rotational atherectomy when greater guide support is necessary.

Aged↗
PubMed1991

Multiple coronary artery aneurysms in an adult associated with extensive thrombus formation resulting in acute myocardial infarction: successful treatment with intracoronary urokinase, intravenous heparin, and oral anticoagulation.

A 37-yr-old white female was admitted to hospital with an evolving anterior myocardial infarction. Coronary arteriography revealed multiple aneurysms in the left anterior descending (and right) coronary arteries. In the left anterior descending artery, there was evidence of extensive thrombus formation. The patient was successfully treated with intracoronary urokinase, intravenous heparin, and oral warfarin. There was partial thrombolysis in 16 hr and complete thrombolysis noted 6 wk later. This case of multiple coronary aneurysms, secondary to presumed Kawasaki disease, is the first documentation of antemortem intra-aneurysmal coronary thrombosis treated successfully by thrombolytic and anticoagulant therapy.

Administration, Oral↗
PubMed1991

Rotational ablation of chronic coronary occlusions.

Rotational ablation was performed successfully in three chronic coronary occlusions. At 3 months follow-up, two of the three lesions were patent. These cases illustrate the overall advantages and unique technical aspects of this device.

Adult↗
PubMed1991

Emergency coronary artery bypass surgery following failed balloon angioplasty: role of the internal mammary artery graft.

During a 4-year period (1986-1989), 3,502 patients had percutaneous transluminal coronary angioplasty (PTCA) in our institution. One hundred nineteen (3.4%) patients required emergency coronary artery bypass graft surgery (CABG) because of abrupt vessel closure following PTCA. Factors associated with vessel closure included lesion angulation greater than or equal to 90 degrees (p less than 0.007), the presence of thrombus (p less than 0.02), or a long (greater than or equal to 2 cm) lesion (p less than 0.03). Of these 119 emergency CABG patients, 108 (91%) arrived in the operating room in a stable condition (group I) and 11 (9%) were in cardiogenic shock (group II). Five (45%) of the group II patients were admitted to the hospital with an acute myocardial infarction and all 11 patients had a higher incidence of multivessel disease (p less than 0.05) and lower left ventricular ejection fraction (p less than 0.001) than group I patients. The overall surgical mortality was 10.1%; however, in group I the mortality was 5.6% and in group II it was 54.5% (p less than 0.001). The vessel that abruptly closed ("culprit vessel") was the left anterior descending (LAD) in 60%, the right coronary artery in 27%, and the left circumflex in 13%. The internal mammary artery was utilized to bypass the culprit artery in 51 (43%) patients, including 50% of the culprit LADs. With group I culprit LAD patients, when the left IMA was the bypass conduit, there were no hospital deaths nor strokes and there was a 6.3% incidence of perioperative infarction.

Adult↗
PubMed1990

Usefulness of tomographic thallium-201 imaging for detection of restenosis after percutaneous transluminal coronary angioplasty.

The role of tomographic thallium-201 exercise and redistribution imaging in the detection of restenosis after percutaneous transluminal coronary angioplasty (PTCA) was evaluated in 116 patients: 61 (53%) with 1- and 55 (47%) with multivessel PTCA, with a total of 185 dilated vessels. Complete revascularization was performed in 89 (77%) and partial revascularization in 27 (23%) of the patients. Restenosis was angiographically demonstrated in 69 (60%) of the patients and 85 (46%) of the vessels 6.4 +/- 3.1 months after PTCA. Disease progression in previously normal vessels was noted in 11 patients. The results were: (1) for detection of restenosis in the group of patients, single-photon emission computed tomographic (SPECT) versus exercise electrocardiographic sensitivity was 93 vs 52% (p less than 0.001), specificity 77 vs 64%, and accuracy 86 vs 57% (p less than 0.001). The results were similar in the complete and partial revascularization groups. (2) SPECT was 86% sensitive, specific and accurate for restenosis detection in specific vessels with comparable results for 1-versus multivessel PTCA and complete versus partial revascularization. Sensitivity, specificity and accuracy were: 89, 95 and 92% for the left anterior descending coronary artery; 88, 79 and 82% for the right coronary artery; and 76, 83 and 85% for the left circumflex coronary artery. Eighty-one percent of the diseased nondilated vessels were correctly identified. (3) Disease progression to greater than 50% stenosis was detected with 91% sensitivity, 84% specificity and 85% accuracy. SPECT thallium-201 imaging is an excellent tool for the detection of restenosis and disease progression after PTCA in the settings of 1- and multivessel angioplasty and complete and partial revascularization.

Angioplasty, Balloon, Coronary↗
PubMed1990

Does percutaneous transluminal coronary angioplasty accelerate atherosclerotic lesions?

Recent reports have suggested that angioplasty may cause or accelerate coronary arterial stenoses secondary to traumatic injury. Ninety-four coronary angiograms performed in a 1 yr period were reviewed in patients who had successful coronary angioplasty 6 to 30 mo (mean 10.7) prior to restudy. Restenosis was found in 43 of 140 dilated lesions (31%) and in 41 of 94 patients (44%). Thirty-three (35%) patients had new or progressive lesions outside the angioplasty site. New or progressive lesions occurred with similar frequency in the arteries that did not have angioplasty (23/155 = 15%) as in the arteries that did (13/127 = 10%; chi-square n.s.). In the arteries which underwent angioplasty, new or progressive lesions occurred as commonly proximal to the PTCA site (7/14, 50%) as distal (6/13, 46%). New or progressive lesions occurred in 29% of patients with concomitant restenosis, and 40% of those without restenosis (chi-square n.s.). No clinical, angiographic, or procedural factors distinguished patients with new and progressive lesions in target vessels from those without these lesions in target vessels. Patients with progressive lesions anywhere in the coronary tree were more likely to have had a shorter duration of anginal symptoms before angioplasty and a family history of coronary disease when compared with patients without progressive atherosclerosis. In conclusion, new and progressive lesions outside the angioplasty site occur after the procedure but appear unrelated to the restenosis process or traumatic injury by angioplasty instrumentation.

Angioplasty, Balloon, Coronary↗
PubMed1990

Cardiac surgery in patients over the age of 80 years.

The risk-benefit relationship of open heart surgery in octogenarians is not well established. Eighty consecutive patients over the age of 80 who underwent cardiac operations under cardiopulmonary bypass were evaluated. Twenty-five patients were in functional class IV, 42 in class III, and 13 in class II. Forty-four patients had only coronary artery bypass grafts (CABG), 12 only aortic valve replacement (AVR), 6 only mitral valve replacement (MVR), 12 CABG and AVR, 4 CABG and MVR, 1 CABG and aneurysmectomy, and 1 had resection of left atrial myxoma. Operative mortality (within 30 days) was 12.5% for the group. Mortality was related to bleeding, left ventricular failure, primary ventricular fibrillation, pulmonary failure, and renal failure. Mortality was higher in patients with (1) advanced functional class, (2) mitral valve replacement, (3) postoperative hemorrhage, and (4) associated pulmonary disease. While a generally conservative approach is recommended for octogenarian patients, many with life-threatening cardiac disease, especially those free of major multisystem illnesses, should not be denied the benefit of surgical treatment.

Aged↗