Biomedical subjects
Publications and source records attributed to G W Vetrovec.
Lyme disease in most cases occurs in the states of Connecticut, Wisconsin, Oregon, California, Missouri and parts of the northeastern coast. Showing the exception to the rule, the authors discuss a case in which a patient acquired the disease on the Eastern Shore of Virginia.
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The principal common pathway for myocardial ischemia is an oxygen supply-demand imbalance; more recently, greater emphasis has been placed on limitations of myocardial blood supply, as well as excessive myocardial oxygen demand. Myocardial ischemia is a metabolic event resulting from inadequate oxygen delivery to local tissues. The physiologic effects of ischemia are observed through abnormalities in left ventricular function, electrocardiographic changes, and often, by angina pectoris. Prognostic and therapeutic outcomes are significantly related to the pathophysiology of the underlying coronary lesion. Because myocardial ischemia often occurs without symptoms, clinical distinctions based on angina stability may more appropriately be represented by stable or unstable ischemic syndromes that incorporate silent ischemia. Stable ischemic syndromes occur secondary to coronary plaques, whereas unstable syndromes are the result of active lesions caused by plaque rupture with local thrombus and vasoreactivity that produce intermittent critical decreases in coronary supply. The prognosis of patients with stable ischemia is related to the extent of myocardium at jeopardy and overall left ventricular function. In contrast, unstable syndromes are associated with a worse short-term prognosis, which may be predictable by the presence of silent ischemia or left ventricular dysfunction or both. Therapeutic decisions based on an improved pathophysiologic understanding of ischemic mechanisms as well as the physiologic impact of therapy on cardiac function can enhance efficacy while avoiding adverse effects. Calcium channel blockers appear to afford certain advantages in the treatment of myocardial ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)
Coronary angioplasty (PTCA) is now applicable to selected patients with multiple vessel disease, total occlusions, tandem lesions and complex branch disease. Operator experience and skill contribute to a high success rate in complex anatomy, but equally important is appropriate case selection based on angiographic review of lesion morphology, branches, extent of coronary artery disease, and left ventricular function. Likewise, during and after the procedure similar angiographic assessment is important to determine resultant lesion morphology, branch anatomy, distal runoff, and adequacy of lesion dilatation. Thus, the outcome of angioplasty is dependent on the operator's ability to opacify the coronary arteries with minimal or no vessel/lesion overlap or foreshortening. Although coronary angiography has become more routine for many angiographers with the advent of angioplasty, the importance of high-quality angiography continues to be a major component for successful angioplasty.
To assess the mechanisms of unstable angina, the coronary angiographic studies in 69 patients with severe unstable angina (prolonged pain or pain at rest) and in 20 patients with stable angina were blindly reviewed to assess the coronary morphologic changes in these syndromes. Coronary angiography was performed an average of 1.7 days from admission and an average of 24 hours from last symptoms of chest pain in patients with unstable angina. Angiographic studies were analyzed for evidence of coronary thrombus (intraluminal filling defects) at significant stenoses in patent vessels or thrombus at sites of total occlusion) and for coronary lesion morphology suggesting a complex or acute lesion (irregular or ill-defined margins, inhomogeneity, haziness or ulceration). Angiographic evidence of coronary thrombus was present in 40 of 69 patients (58%) with unstable angina: 31 (45%) had intraluminal filling defects and 9 (13%) had thrombotic total occlusion with well-developed collaterals present. Only 1 of 20 patients (5%) with stable angina had evidence of thrombus (p less than 0.001). Complex lesions were present in 18 other unstable patients (26%) and in 2 other patients (10%) with stable angina who did not have angiographic evidence of thrombus. Overall, 58 of 69 patients (84%) with unstable angina had morphologic findings suggesting an acute process (thrombus or complex lesion) compared with 3 of 20 patients (15%) with stable angina, p less than 0.0001. Thus, unstable angina is associated with a high prevalence of angiographic coronary thrombus and complex lesions suggesting an acute process, in contrast to stable angina.(ABSTRACT TRUNCATED AT 250 WORDS)
The Nifedipine-Total Ischemia Awareness Program was designed to evaluate the prevalence, prognostic implications and effect of therapy on painful and painless myocardial ischemic episodes in a nationwide study of patients with angina pectoris. Three hundred forty-eight patients with at least 2 anginal attacks/week while taking antianginal medications were enrolled at 53 participating centers between September 1, 1986 and March 31, 1988; 312 of the 348 patients formed the study group, while 36 patients formed the control group. At least 1 episode of ST-segment depression during two 48-hour periods of Holter monitoring was present in 136 of the 312 patients in the study group. In these 136 patients, there was a total of 372 episodes of ST-segment depression, of which only 69 (18%) were painful; 85% of the 136 patients had either painless episodes only or both painless and painful episodes. Despite apparently adequate antianginal therapy, 48 patients had greater than or equal to 3 episodes of ST-segment depression/48 hours of ambulatory electrocardiographic monitoring, and 38 patients greater than 60 minutes of ST-segment depression. After nifedipine was administered, there was a 23% reduction in the mean number of episodes of ST-segment depression (2.7 +/- 0.3 to 2.1 +/- 0.2, p less than 0.01). The most pronounced effects were found in the 48 patients with greater than or equal to 3 episodes of ST-segment depression and the 38 patients with greater than or equal to 60 minutes of total ischemic time.(ABSTRACT TRUNCATED AT 250 WORDS)
The nifedipine gastrointestinal therapeutic system (GITS) is a promising new formulation that provides continuous release of nifedipine over the course of 24 hours with once-daily dosing. Results from a 14-week, open-label, crossover multicenter trial completed by 91 patients with chronic stable angina pectoris demonstrate that patients treated with standard nifedipine capsules may be switched to equivalent total 24-hour doses of nifedipine GITS and achieve comparable or improved efficacy (due to improved compliance) with a more favorable side-effects profile. Furthermore, in a subset of 10 patients who underwent sequential exercise testing, exercise responses obtained throughout 12 weeks of treatment with nifedipine GITS were comparable to measurements obtained during treatment with nifedipine capsules and demonstrated that tolerance did not occur. These patients also experienced significantly fewer vasodilatory side effects during treatment with nifedipine GITS compared with nifedipine capsules. Thus, nifedipine GITS represents a sound pharmacologic approach to the management of ischemic disease; and with once-daily dosing and a favorable side-effect profile this agent affords the potential for better patient compliance and efficacy without concern about the development of tolerance.
This prospective series of results and complications of coronary arteriography from the Registry of the Society for Cardiac Angiography and Interventions is the largest ever reported. Since the initial report published in 1982, the results of coronary artery surgery and angioplasty have improved and therefore older and more symptomatic patients are referred for coronary arteriography. More patients are now studied by the femoral approach, and the major complications of the techniques are similar. Despite studying older and higher-risk patients, the complications are remarkably similar to those reported in the older series. Because of the sicker patients being studied, it is probably unlikely that the complication rate will decrease further in the future. The Society for Cardiac Angiography and Interventions will continue its Registry to follow complication rates of both established and new procedure.
In a 42-month period, 218 deaths occurred in 222,553 patients undergoing coronary arteriography (0.098%). Age greater than 60 years, NYHA Class IV function, presence of left main coronary disease, and ejection fraction less than 30% all significantly increased the risk of the procedure. Sex and approach (brachial or femoral) used for the catheterization did not affect mortality. Since the SCAI report in 1982, the death rate has dropped significantly in high-risk patients. Low-risk patients (NYHA Class I or normal coronary arteries) who died generally were elderly or had associated valvular heart disease.
To assess clinical and angiographic features of early occlusion after percutaneous transluminal coronary angioplasty (PTCA), 25 successful PTCA procedures (3%) with early occlusion were analyzed from a PTCA population of 917. Twenty patients (80%) had unstable angina, while 12 (48%) had a recent (less than 1 mo) myocardial infarction subtended by the PTCA vessel. All patients received a calcium blocker, aspirin, dipyridamole, and heparin prior to PTCA. In 20 of 25 patients (80%), occlusion occurred in the catheterization laboratory, while five occurred out of laboratory, three within 5 hours and 1 each within 24 and 48 hours. Angiographic features before PTCA included complex lesions (hazy, stained, or ulcerated) in 12 (48%) and intracoronary filling defects in eight patients (32%). Post-PTCA intracoronary filling defects were present in 17 dilated stenoses (68%). Compared to a consecutive control population of 100 patients with similar demographics but without acute occlusion, the frequency of unstable angina, acute myocardial infarction, and filling defects was greater in patients with early occlusion (P less than .001 for all). Intracoronary nitroglycerin was utilized in all patients with reopening in only one (4%), while bypass surgery was performed in five (20%). Intravenous streptokinase was administered to two patients with reperfusion in one. Immediate repeat PTCA was successful in 15 of 17 patients (88%). In summary, recent unstable angina, myocardial infarction, complex lesions or intracoronary filling defects before and particularly after PTCA all suggest an association of clot with early occlusion. Immediate repeat PTCA is frequently successful.
In order to determine the reliability of a single arterial access technique for hemodynamic assessment of aortic stenosis, data obtained from this method was compared with that from dual arterial access in 13 patients. A 59 cm long, 8 Fr. Mullins Transseptal Sheath (MTS) was placed in the ascending aorta (AA) and a 5 Fr. pigtail catheter advanced through the MTS (using a hemostatic "Y" adapter) into the left ventricle for simultaneous pressure recordings. Another 5 Fr. pigtail catheter (PTC) was advanced in the AA from the contralateral femoral artery. Peak pressures, AA pressure-tracing characteristics, mean gradients, and the aortic valve area using tracings from the MTS and the PTC were compared. Peak pressures 120 +/- 8 vs. 119 +/- 8 mmHg (r = .998), "T" time .16 +/- .01 vs. .15 +/- .01 sec. (r = .913), "U" time .36 +/- .02 vs. .36 +/- .02 sec. (r = .983), mean gradients 38.4 +/- 6.1 vs. 39.6 +/- 6.9 mmHg (r = .990) and the AV area .78 +/- .08 vs. 79 +/- .08 cm2 (r = .994) were similar. Therefore, this single arterial technique provides data comparable to the traditional dual access system for hemodynamic assessment of aortic stenosis.
The functional efficacy of a conventional 7F (high flow) coronary catheter (hand injection) was compared with a 5F (high flow) catheter using hand and powered injection in 29 patients with ischemic heart disease. Patients were randomized to 5F or 7F catheters as the initial catheter. Consecutive comparative coronary angiograms were performed in the 15 degrees right anterior oblique (RAO) view using Judkin's technique. Visual diagnostic grade (Grade 1 = Diagnostic, Grade 2 = Equivocal, Grade 3 = Nondiagnostic), vessel filling, vessel density (using a densitometer and corrected for background), streaming, and dislodgement were all evaluated independently by two experienced angiographers with correlation of results. Mean diagnostic grade (1.31 +/- 0.48) was significantly better with the 7F compared to 5F (hand) 1.72 +/- 0.81 and 5F (power) 2.00 +/- 0.71 (P less than or equal to 0.05) for each. Streaming was seen in 55% of injections with 5F (hand) versus 88.5% with 5F (power) and 20.7% with 7F. Measured vessel density was not different for the two catheters. Coronary injection dislodgement occurred significantly more often with 5F power injections than with hand injection of either catheter. Finally, in 6 (30%) of 20 patients in which the 5F was randomly the second catheter used, the operator had to revert to the 7F catheter in order to obtain adequate images. In conclusion, angiographic quality is reduced with 5F catheters compared to 7F high flow in certain patients. Thus, to achieve optimal diagnostic angiograms, larger lumen catheters may be required during certain procedures initially begun with 5F catheters.
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The immediate effects of successful percutaneous transluminal coronary angioplasty on global and regional left ventricular function were assessed by comparing 30 degrees right anterior oblique left ventricular angiograms performed immediately before and after angioplasty on 39 patients undergoing 42 successful procedures. Mean (+/- SD) lesion stenosis decreased from 88 +/- 10% to 35 +/- 11% (p less than or equal to 0.001), whereas left ventricular ejection fraction increased from 57 +/- 11% to 64 +/- 10% (p less than or equal to 0.001) for the entire group. Left ventricular functional changes were further subgrouped according to stability of angina. Eighteen procedures were performed on 17 patients with stable angina: 24 procedures were performed on 22 patients with unstable angina defined as angina at rest or on minimal activity or recently accelerated angina. There were no significant subgroup differences in mean age, gender ratio, vessel anatomy, drug therapy or extent of coronary stenosis before or after angioplasty. Global ejection fraction increased significantly for the unstable group (from 54 +/- 11% to 66 +/- 9%, p less than or equal to 0.001) but was unchanged for the stable group (from 61 +/- 9% to 61 +/- 11%, p = NS). In unstable angina, regional ejection fraction (segmental area method) increased for both jeopardized (from 37 +/- 11% to 52 +/- 9%, p less than or equal to 0.001) and nonjeopardized myocardial segments (from 43 +/- 13% to 51 +/- 13%, p less than or equal to 0.001), but improvement was significantly (p less than or equal to 0.02) greater in jeopardized segments.(ABSTRACT TRUNCATED AT 250 WORDS)
Two cases of distal right coronary artery (RCA) bifurcational stenoses involving ostia of the posterolateral (PLA) and the posterior descending (PDA) branches in patients who underwent successful coronary angioplasty using a double-wire technique are reported. A single guiding catheter and sequential balloon inflations were utilized in one, and two guiding catheters and simultaneous balloon inflations in the other. The indications, techniques, and outcomes are described.
This case report describes a technique for guiding catheter exchange while angioplasty extended guidewire access is maintained across a coronary artery stenosis with a 245-cm-0.035-in.-long wire in the aorta to exchange for a more favorable guiding catheter. The indications, technique, and outcome of a case are described; it illustrates the usefulness of maintaining angioplasty guidewire access in a difficult-to-cross coronary stenosis.
The following report describes the use of the high flow injection characteristics of a coronary angioplasty guiding catheter to improve coronary opacification in a patient with exceedingly high coronary runoff. This technique offers improved coronary visualization in special cases.
Severe coronary artery disease (CAD) and frequent ventricular premature beats (VPBs) on ambulatory ECG monitoring in the late hospital phase after myocardial infarction are independent predictors of prognosis. To study the relationship between extent of CAD and VPB frequency, 128 consecutive (91 men, 37 women) patients surviving 6 days after myocardial infarction underwent 24-hour ECG, coronary angiography, and left ventriculography. CAD was graded as zero to one-, two-, and three-vessel (V), and also by a previously validated "jeopardy score" with 0 to 12 as grades of incremental CAD severity. Average VPB frequency was significantly correlated with CAD by V, CAD by jeopardy score, and by left ventricular ejection fraction (p less than 0.01 for all three). With the use of a multivariate ordinal logistic regression model, both VPB frequency and left ventricular ejection fraction were found to have independent association with CAD. The median VPB frequency was 1/hr, 0.6/hr, and 6/hr in zero to one-, two-, and three-V CAD, respectively (zero to one- and two-V CAD vs three-V CAD p less than 0.01, one-V CAD vs two-V CAD p = NS). In conclusion, frequent VPBs following myocardial infarction are associated with extensive CAD and are independent of left ventricular ejection fraction. Therefore, the prognostic value of frequent VPBs may be related to severe underlying ischemic disease.