Search PubMed⌕ Search

Biomedical subjects

L S Dean

Publications and source records attributed to L S Dean.

At least 55 records · Page 3Linked to original sources
PubMed1994

Percutaneous transvenous mitral commissurotomy: a comparison to the closed and open surgical techniques.

Percutaneous transvenous mitral commissurotomy, first described in 1984, has gained acceptance as a mode of treatment for patients with symptomatic, severe rheumatic mitral stenosis. The closed surgical technique, one of the oldest cardiovascular surgical procedures, is similar in mechanism to the percutaneous technique. Nonrandomized and randomized trials are reviewed and percutaneous transvenous mitral commissurotomy compares favorably with the closed technique, both in acute hemodynamic changes as well as in long-term result. Although the percutaneous technique is quite different from the open surgical technique, comparisons are appropriate since this is the technique of choice in most industrialized countries. Randomized trials comparing the open versus the percutaneous technique have limited numbers of patients and follow-up, but preliminary data would suggest that the two techniques compare favorably in appropriately selected patients. It appears that percutaneous transvenous mitral commissurotomy has a definite place in the treatment of appropriately selected patients with symptomatic rheumatic mitral stenosis performed in experienced centers.

Catheterization↗
PubMed1993

Is traditionally defined complete revascularization needed for patients with multivessel disease treated by elective coronary angioplasty? Multivessel Angioplasty Prognosis Study (MAPS) Group.

OBJECTIVES: The purpose of this study was to determine the effect of incomplete revascularization by percutaneous transluminal coronary angioplasty in patients with multivessel disease on adverse long-term cardiac events (death, coronary artery bypass surgery or myocardial infarction) and to develop an optimal definition of adequate revascularization based on clinical outcome. BACKGROUND: The effect of incomplete coronary revascularization by coronary angioplasty on long-term adverse clinical events remains controversial. METHODS: Three hundred seventy well characterized patients were followed-up for 27 +/- 16 months after angioplasty. Mean patient age was 58 +/- 11 years; 72% were male; 70% had two-vessel disease (> or = 50% diameter stenosis by caliper measurement); and the mean left ventricular ejection fraction was 58 +/- 11% (range 20% to 85%). Angioplasty was successfully accomplished in 339 patients (91.6%), but complete revascularization by the standard definition (no residual > or = 50% stenosis in a coronary artery > or = 1.5 mm in diameter) was achieved in only 91 patients (25%). RESULTS: Three-year event-free survival (i.e., freedom from death, myocardial infarction, coronary artery bypass surgery) in the entire cohort was 76.5%. By the standard definition, complete revascularization was strongly and negatively associated (p = 0.003) with long-term cardiac events, even after correction for the effects of other independent correlates of events, using Cox proportional hazard regression analysis. Seventeen other definitions, evaluating the severity and extent of residual stenoses and whether they were associated with contractile myocardium, were tested to find that which best stratified late event-free survival and had an outcome with complete revascularization no worse than that associated with the standard definition. The best definition for the entire cohort, having more predictive value than the standard definition, allowed < 10% of estimated left ventricular mass to be served by vessels with mild stenoses (< 60%) without being considered "incomplete." CONCLUSIONS: Mild stenoses in coronary arteries > or = 1.5 mm in diameter serving modest amounts of myocardium do not appear to need to be revascularized to achieve good long-term outcome with coronary angioplasty. Hence, angioplasty in such lesions may not be justified except when they are documented to cause life-style-limiting angina, and the standard definition of complete revascularization by angioplasty appears to be suboptimal. The importance of optimally defined adequate revascularization should be considered in the interpretation of the results of randomized trials assessing the clinical efficacy of coronary angioplasty compared with that of other modalities of therapy.

Actuarial Analysis↗
PubMed1993

Clinically guided closure of femoral arterial pseudoaneurysms complicating cardiac catheterization and coronary angioplasty.

Femoral artery pseudoaneurysm formation is a significant problem in patients undergoing cardiac catheterization and interventional cardiac procedures. It is especially more common with the use of anticoagulant and antiplatelet therapy and the use of intracoronary stents. We describe our initial experience with clinically guided bedside compression of femoral pseudoaneurysms in such patients. Eleven patients, 10 undergoing coronary angioplasty (including 3 with intracoronary stents) and 1 undergoing diagnostic cardiac catheterization, developed a femoral pseudoaneurysm. All patients had a femoral bruit and 9 had an expansile groin hematoma. The diagnosis was confirmed in each case by Doppler ultrasound. Seven patients were receiving heparin while 4 were on oral anticoagulants at the time of detection of the pseudoaneurysm. These patients underwent clinically guided graded external compression to close the pseudoaneurysm neck while maintaining femoral arterial flow. External compression for 104.1 +/- 63 min resulted in successful clinical resolution of pseudoaneurysm in all patients without complications. The results were confirmed by Doppler ultrasound at least 12 hr later. Bedside compression of femoral pseudoaneurysms guided by clinical clues is simple and appears to be an effective and safe technique to manage this iatrogenic problem.

Aged↗
PubMed1992

Reduction of ischemia with a new flow-adjustable hemoperfusion pump during coronary angioplasty. The Coronary Hemoperfusion Ischemia Prevention Study (CHIPS) Investigators.

A new flow-adjustable pump for coronary hemoperfusion to prevent ischemia during routine coronary angioplasty was evaluated in a multicenter prospective study of 110 patients. The protocol included patients who had angina or ST segment elevation during a control balloon inflation of less than or equal to 3 min. Hemoperfusion was performed by means of a new large lumen angioplasty catheter utilizing the patient's renal vein or femoral artery blood. Vessels perfused were the left anterior descending coronary artery (n = 74), right coronary artery (n = 39), left circumflex artery (n = 9) and coronary vein grafts (n = 15). Mean (+/- SD) perfusion flow was 41 +/- 9 ml/min (range 17 to 70); mean perfusion time was 9.3 +/- 4 min (median 8.5, range 2 to 30). Chest pain score (0 to 4) decreased from 2.9 +/- 1 to 1.4 +/- 1 during hemoperfusion (p less than 0.001); ST segment elevation score (0 to 4) decreased from 2.6 +/- 1 to 0.7 +/- 1 (p less than 0.005) and inflation time increased from 1.3 +/- 0.9 to 7 +/- 4 min, (p less than 0.001). At least a 50% increase in tolerated inflation time was obtained in 104 patients (95%). Free plasma hemoglobin and creatine kinase levels did not increase significantly over baseline values. Angioplasty was successful in 107 patients (97%), with mean stenosis reduced from 87 +/- 11% to 20 +/- 17%; 3 patients had urgent bypass surgery, 2 (1.8%) had a myocardial infarction (1 Q wave, 1 non-Q wave) and 2 (1.8%) died later in the hospital of probable noncoronary causes.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Nonsurgical closure of femoral pseudoaneurysms complicating cardiac catheterization and percutaneous transluminal coronary angioplasty.

OBJECTIVES: This study was performed to describe the initial experience and follow-up of ultrasound-guided compression of pseudoaneurysms in patients receiving systemic anticoagulant or antiplatelet therapy, or both, after recent cardiac catheterization or percutaneous transluminal coronary angioplasty. BACKGROUND: Femoral artery pseudoaneurysm formation after an interventional procedure is becoming more common as larger caliber catheters and prolonged anticoagulant and antiplatelet therapy are being used. Traditional treatment of this complication has been surgical repair. This study describes a new method of closing femoral pseudoaneurysms by using external compression guided by Doppler color flow imaging. METHODS: Fifteen patients, 3 undergoing cardiac catheterization and 12 undergoing coronary angioplasty, developed an expansile groin mass at the vascular access site diagnosed as a femoral artery pseudoaneurysm by Doppler ultrasound. Seven of the patients had undergone coronary stenting and were receiving postprocedural anticoagulant therapy. These patients underwent progressive graded mechanical (C-clamp) external compression guided by ultrasound. The mechanical compression was titrated to obliterate the vascular tracts to these aneurysms and maintain adequate flow in the femoral artery. RESULTS: After an average compression time of 30 min (range 10 to 120), these tracts remained closed. Follow-up ultrasound examination at 24 h or later confirmed continued closure in all. CONCLUSIONS: This study suggests that nonsurgical closure of femoral pseudoaneurysms is feasible. This technique may be valuable in managing vascular access-related complications after diagnostic and interventional procedures, even in patients requiring prolonged anticoagulant therapy.

Adult↗
PubMed1992

Intracoronary stenting for acute and threatened closure complicating percutaneous transluminal coronary angioplasty.

BACKGROUND. Acute closure remains a significant limitation of percutaneous transluminal coronary angioplasty (PTCA) and underlies the majority of ischemic complications. This study details the clinical and angiographic characteristics of a series of patients receiving an intracoronary stent device to manage acute and threatened closure and presents the early clinical results. METHODS AND RESULTS. From October 1989 through June 1991, 115 patients undergoing PTCA received intracoronary stents to treat acute or threatened closure in 119 vessels. Sixty-three percent had multivessel coronary disease, 33 (29%) had undergone prior coronary artery bypass grafting (CABG), and 52 (45%) had had previous PTCA. Using the American College of Cardiology/American Heart Association (ACC/AHA) classification, 15% of lesions were class A, 55% were class B, and 30% were class C. Eight patients were referred with severe coronary dissection and unstable angina after PTCA at other institutions. Acute closure was defined as occlusion of the vessel with TIMI (Thrombolysis in Myocardial Infarction) 0 or 1 flow immediately before stent placement. Threatened closure required two or more of the following criteria: 1) a residual stenosis greater than 50%, 2) TIMI grade 2 flow, 3) angiographic dissection comprising extraluminal dye extravasation and/or a length of greater than 15 mm, 4) evidence of clinical ischemia (either typical angina or ECG changes). Twelve vessels (10%) met the criteria for acute closure, and 87 vessels (73%) satisfied the criteria for threatened closure. Twenty vessels (17%) failed to meet two criteria. Stenting produced optimal angiographic results in 111 vessels (93%), with mean diameter stenosis (+/- 1 SD) reduced from 83 +/- 12% before to 18 +/- 29% after stenting. Overall, in-hospital mortality was 1.7% and CABG was required in 4.2%; Q wave myocardial infarction (MI) occurred in 7% and non-Q wave MI in 9%. Stent thrombosis occurred in nine patients (7.6%). For the 108 patients who presented to the catheterization laboratory without evolving MI, Q wave MI occurred in 4% and non-Q wave MI occurred in 7%. Angiographic follow-up has been performed in 81 eligible patients (76%), and 34 patients (41%) had a lesion of greater than or equal to 50%. CONCLUSIONS. This stent may be a useful adjunct to balloon dilatation in acute or threatened closure. Randomized studies comparing this stent with alternative technologies are required.

Angioplasty, Balloon, Coronary↗
PubMed1991

Value and limitations of color Doppler echocardiography in the evaluation of percutaneous balloon mitral valvuloplasty for isolated mitral stenosis.

The limitations of 2-dimensional and pulsed Doppler echocardiography in patients undergoing mitral valvuloplasty are well known. This study was undertaken to assess the value of color Doppler flow imaging in 36 symptomatic mitral stenosis patients who subsequently underwent successful balloon mitral valvuloplasty by comparing the results to those obtained at cardiac catheterization. Color Doppler-guided conventional Doppler assessment agreed well with cardiac catheterization results in classifying mitral stenosis as mild, moderately severe and severe, both before and after valvuloplasty. Color Doppler was also useful in identifying patients who had moderate to severe mitral regurgitation before and after valvuloplasty. Color Doppler flow mapping was more sensitive than oximetry in the detection of iatrogenic atrial septal defects, which were noted in 25 patients. The defects of those patients with smaller defects by color Doppler (diameter less than 0.7 cm) or echocardiographic shunt volume less than 0.7 liters/min tended to close, usually within 6 months, as opposed to those with larger defects or higher shunt volumes, which tended to persist. Echocardiographic shunt volumes revealed a fair correlation with oximetric results.

Cardiac Catheterization↗
PubMed1991

Outcome probabilities and life history after surgical mitral commissurotomy: implications for balloon commissurotomy.

From 1967 to 1988, 339 patients with mitral stenosis underwent surgical commissurotomy, 103 with a closed and 236 with an open technique. The 1 month and 1, 5, 10 and 20 year overall survival rate was 99.7%, 99%, 95%, 87% and 59%, respectively, and the technique (open versus closed) was not a risk factor. Technique was also not a risk factor for a second mitral commissurotomy, subsequent mitral valve replacement, thromboembolism or poor functional status. Risk factors were older age at commissurotomy, black race, higher pulmonary vascular resistance, mitral leaflet calcification, left ventricular enlargement and postcommissurotomy mitral incompetence. The closed technique was a risk factor for mitral incompetence immediately after commissurotomy, but important incompetence developed in only 2 of the 103 patients undergoing closed commissurotomy. Mitral valve replacement was not required within 10 years in 78% of patients and within 20 years in 47%. Despite some increased prevalence of postcommissurotomy mitral incompetence and particularly in view of the considerable long-term likelihood of mitral valve replacement, initial therapy for most patients with mitral stenosis should probably be surgical closed (or percutaneous balloon) mitral commissurotomy. The equations developed in the present study can be used to predict and compare outcome probability after percutaneous balloon commissurotomy with that after surgical commissurotomy and to compare these with outcome probability after mitral valve replacement.

Catheterization↗
PubMed1991

The influence of balloon inflation duration on the acute angiographic result of percutaneous transluminal coronary angioplasty.

This study was performed to evaluate the importance of the duration of balloon inflation during PTCA, by comparing two common inflation durations. Patients were randomized to a 30-second inflation protocol (group I, 83 procedures, 109 lesions), or a 60-second protocol (group II, 83 procedures, 115 lesions). There were no differences in baseline characteristics between the two groups, and no subsequent differences in mean inflation number (3.4 +/- 1.6 vs 3.1 +/- 1.6), residual stenosis (34% +/- 17% vs 33% +/- 16%), presence of dissection (29% vs 34%), or clinical success (89% vs 84%), group I versus group II, respectively. The 30-second inflations caused significantly less chest pain score (147 +/- 239 vs 399 +/- 516, P less than 0.001), and ST segment alteration (75 +/- 94 seconds vs 136 +/- 163, P less than 0.05). These results indicate that 60-second inflations do not produce a superior result to 30-second inflations. Furthermore, shorter inflations are much better tolerated.

Aged↗
PubMed1989

Severe aortic regurgitation complicating percutaneous aortic valve valvuloplasty.

An 88-year-old patient undergoing percutaneous aortic balloon valvuloplasty of a tricuspid aortic valve is described. The patient had mild aortic regurgitation prior to the procedure but developed severe aortic regurgitation after balloon dilatation of the valve. At the time of surgery there was no anatomic disruption of the valve or supporting structures. Development of severe aortic incompetence following balloon valvuloplasty has not been previously reported.

Aged↗
PubMed1988

Cortical blindness after left internal mammary artery to left anterior descending coronary artery graft angiography.

We describe a case of transient cortical blindness following internal mammary artery to left anterior descending coronary artery graft angiography. This dramatic, infrequent, and self-limiting complication so far has not been described in the cardiovascular literature. In the present era of internal mammary artery use for the left coronary artery grafting, the angiographer should be familiar with the diagnosis, prevention, and management of complications previously seen mostly during the posterior cerebral circulation angiography.

Angiography↗
PubMed1987

Resistance-training experience and the pressor response during resistance exercise.

The purpose of this study was to examine the effects previous resistance-training experience has on the cardiovascular responses to resistance-training exercises. To investigate this, the intra-arterial blood pressure response of four body builders (BB), six novice weight-trained individuals (NT), and six sedentary controls (SC) were monitored during performance of one-arm overhead presses and one-leg knee extensions. One repetition at the maximal weight possible (1 RM) and sets to voluntary fatigue at 90, 80, 70, and 50% of 1 RM were performed. Across groups, the BB demonstrated a significantly (P less than 0.05) lower peak and a lesser magnitude of response (changes from rest to peak) for systolic and diastolic blood pressures than the the NT and SC groups during both exercises. The BB also demonstrated significantly lower values across groups for peak heart rate and magnitude of heart rate response during arm presses. During knee extensions across groups, peak heart rate but not magnitude of the heart rate response was significantly lower in the BB. The results indicate that previous weight-training experience reduces the pressor response to dynamic resistance exercises.

Adult↗