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D S Baim

Publications and source records attributed to D S Baim.

At least 127 records · Page 7Linked to original sources
PubMed1993

Economics of elective coronary revascularization. Comparison of costs and charges for conventional angioplasty, directional atherectomy, stenting and bypass surgery.

OBJECTIVES: This study was designed to evaluate more closely the true in-hospital costs of elective revascularization by directional coronary atherectomy and intracoronary stenting and to compare these costs with those of the traditional revascularization alternatives (i.e., conventional balloon angioplasty and coronary artery bypass surgery). BACKGROUND: Previous studies have suggested that total hospital charges for directional coronary atherectomy or intracoronary stenting are significantly higher than those for conventional angioplasty. However, hospital charges do not necessarily reflect true economic costs, and their use may provide misleading data with regard to cost-effectiveness. METHODS: We analyzed in-hospital charges from the itemized hospital accounts of 300 patients undergoing elective angioplasty, directional atherectomy, Palmaz-Schatz coronary stenting or bypass surgery between January 1, 1990 and December 31, 1991. Costs were then derived by adjusting itemized patient accounts for department-specific cost/charge ratios. Catheterization laboratory costs were based on actual resource consumption, and daily room costs were adjusted for the intensity of nursing services provided. RESULTS: Length of hospital stay was similar for atherectomy (2.3 +/- 1.5 days) and conventional angioplasty (2.6 +/- 1.7 days) but significantly longer for stenting (5.5 +/- 2.6 days, p < 0.05). Total costs were also significantly higher for coronary stenting ($7,878 +/- $3,270, median $6,699, p < 0.05) than for angioplasty ($5,396 +/- $2,829, median $4,753) or atherectomy ($5,726 +/- $2,716, median $4,986). However, length of stay, resource consumption (laboratory and radiologic testing, drugs, blood products, for example) and total costs for bypass surgery were still greater than for any of the percutaneous interventional procedures. CONCLUSIONS: In contrast to previous studies utilizing only hospital charges, the in-hospital costs of angioplasty and directional coronary atherectomy were similar. Although the cost of coronary stenting was approximately $2,500 higher than that of conventional angioplasty, the magnitude of this difference was smaller than the $6,300 increment previously suggested on the basis of analysis of hospital charges. These findings reflect the inherent discrepancies between cost-based and charge-based methodologies and may have important implications for future studies evaluating the relative cost-effectiveness of newer coronary interventions.

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PubMed1993

Generalized model of restenosis after conventional balloon angioplasty, stenting and directional atherectomy.

OBJECTIVES: This study was designed to extend the results of a quantitative model originally developed for restenosis after stenting or atherectomy to include restenosis after conventional balloon angioplasty. BACKGROUND: We have previously described a continuous regression model that explains late (6-month) lumen narrowing as the difference between the immediate gain and the subsequent normally distributed late loss in lumen diameter after Palmaz-Schatz stenting or directional atherectomy. METHODS: Lumen diameter was measured immediately before and after coronary intervention on 524 consecutive lesions including those treated by Palmaz-Schatz stenting (102), directional atherectomy (134) and conventional balloon angioplasty (288). Of these lesions, 475 (91%) underwent follow-up angiography 3 to 6 months after treatment. The immediate increase in lumen diameter produced by the intervention (immediate gain) and the subsequent reduction in lumen diameter between the time of intervention to follow-up angiography (late loss) were examined. Association between demographic or angiographic variables and continuous measures of restenosis (late lumen diameter or late percent stenosis) was tested with linear regression techniques; a traditional binary measure of restenosis (late diameter stenosis > or = 50%) was evaluated with logistic regression analysis. RESULTS: Regression models relating late lumen diameter to the immediate lumen result were successfully fitted to all segments studied. According to these models, three indexes of restenosis (late lumen diameter, late percent stenosis and binary restenosis) were found to depend solely on the immediate lumen diameter after the procedure and the immediate residual percent stenosis, but not on the specific intervention used. Moreover, the late loss in lumen diameter was found to vary directly with the immediate gain provided by an intervention, and the "loss index" (a measure that corrects for differences in immediate gain) was uniform among all three interventions. CONCLUSIONS: The quantitative model originally developed for restenosis after stenting or atherectomy may thus be generalized to include conventional balloon angioplasty. It shows that the apparent differences in restenosis among the three interventions studied are due solely to differences in the immediate result provided and not to differences in the behavior of subsequent late loss. Moreover, although the late loss in lumen diameter was found to correlate with differences in the immediate gain provided by an intervention, the "loss index" (a measure that corrects for differences in acute gain) was uniform across all three interventions. It is thus the immediate result (and not the procedure used to obtain that result) that determines late outcome after coronary intervention.

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PubMed1993

A prospective study of the clinical outcome of femoral pseudoaneurysms and arteriovenous fistulas induced by arterial puncture.

PURPOSE: Although spontaneous thrombosis of femoral false aneurysms (FAs) and arteriovenous fistulas (AVFs) has been reported, the frequency of this occurrence is unknown. This prospective study was designed to establish the natural history of FA and AVF and to evaluate factors that might predict eventual thrombosis of these lesions. METHODS: Twenty-two patients with either femoral FAs (n = 16) or AVFs (n = 6) induced by percutaneous arterial punctures were evaluated prospectively. After an initial duplex scan, all patients were monitored with serial scans, either in hospital or weekly as outpatients, depending on the stability of the process. Operative repair was performed for the following indications: (1) a greater than 100% increase in size of a FA by duplex scan, (2) the development of symptoms, or (3) continued patency of the lesion after 2 months of observation. RESULTS: Nine of 16 FAs and four of six AVFs closed spontaneously; FAs greater than 6 cm3 (1.8 cm in diameter) required repair more often (p = 0.065). However, size was not an absolute predictor of the need for repair because two small aneurysms (1.6 and 0.7 cm3) remained patent, although both patients were discharged safely from the hospital, and two large aneurysms (13.2 and 10.7 cm3) thrombosed spontaneously. Three of seven patients whose aneurysms required repair received anticoagulation continuously from the time of catheterization until repair became necessary. None of the patients whose FAs closed spontaneously were receiving anticoagulants at the time of thrombosis (p = 0.02). Neither length of the FA neck, velocity in the FA cavity, size of original arterial puncture, nor velocity in the AVF correlated with thrombosis. CONCLUSIONS: We conclude that (1) all FAs do not thrombose spontaneously and at least one third require surgical repair, (2) patients receiving continuous anticoagulation should undergo aneurysm repair, (3) discharge of patients with FAs less than 6 cm3 is safe (the majority of these FAs will eventually thrombose spontaneously), and (4) many AVFs close spontaneously and repair is not required unless symptoms or signs of progressive enlargement develop.

Aneurysm, False↗
PubMed1993

New technologies in interventional cardiology.

New technologies for interventional cardiology include metallic intraluminal supports (stents), mechanical devices used for plaque removal (atherectomy), and photoablative devices (lasers). Several individual devices in each category are in active clinical investigation and appear to provide safe and effective treatment for many problems that have continued to plague conventional balloon angioplasty. These include failure to dilate eccentric, rigid, or diffuse stenoses; abrupt closure of the dilated segment; and restenosis after successful dilatation. Working with these devices, physicians have learned not only how to use them optimally but a great deal about the biology of restenosis and the manner in which new interventional devices should be evaluated. Although none of the new technologies is likely to replace balloon angioplasty, which has demonstrated broad applicability, success, and safety, the selective use of new devices seems certain to enhance the possibilities for percutaneous transluminal revascularization.

Angioplasty, Laser↗
PubMed1993

A predictive method for estimating the late angiographic results of coronary intervention despite incomplete ascertainment.

BACKGROUND: Investigations of coronary restenosis typically use late (4-6-month) angiographic end points. Since only 50-80% of patients generally undergo repeat angiography, however, restenosis for the population as a whole is usually estimated by assuming that nonrestudied and restudied patients are similar. If restudied and nonrestudied patients differ, incomplete angiographic follow-up can yield an erroneous estimate of restenosis. No suitable method has yet been devised to detect and correct these errors. METHODS AND RESULTS: We studied the clinical indications for angiographic restudy in an actual series of 301 treated lesions in 267 consecutive patients who underwent either Palmaz-Schatz stenting (126 patients) or directional coronary atherectomy (141 patients) at our institution. While only 249 (83%) treated segments underwent 4-6-month angiographic follow-up, all had clinical follow-up that described whether specific indications for restudy were present. Patients who had no clinical indications for such restudy were designated as having elective follow-up. In contrast, patients who had recurrent symptoms or positive exercise studies and were scheduled for repeat angiography at the independent recommendation of their referring cardiologist were designated as having nonelective follow-up. Mean late percent stenosis or binary restenosis rate (> 50% diameter stenosis) was determined for elective versus nonelective lesions that underwent follow-up angiography. These values were then used to input the behavior of the nonrestudied lesions according to their clinical status. From these imputations, a "predictive" model was developed to estimate the mean restenosis values that would have been found had the entire population actually undergone angiographic follow-up. Comparisons between the estimates of this predictive method and the traditional method that uses only the actual angiographic data demonstrate how alterations in various parameters influence the selection bias caused by incomplete angiographic follow-up. Of the 301 lesions available for follow-up, 100 of the 103 (97%) nonelective versus 149 of the 198 (75%, p < 0.001) elective lesions actually underwent angiographic follow-up. Mean follow-up percent stenosis (50% versus 27%) and the binary restenosis rate (53% versus 13%) differed significantly for the nonelective versus the elective lesions, respectively (both p < 0.001). Even at the fairly high (83%) angiographic follow-up rate, elective versus nonelective status was thus a confounder that caused differences between the restenosis rate estimated by the traditional (29.1%; 95% CI: 23.4, 34.7) and the predictive methods (26.3%; 95% CI: 21.4, 31.1). Larger (and even statistically significant) differences may be present under the conditions that exist in many current studies. CONCLUSIONS: Restenosis trials with < 90% angiographic follow-up suffer from selection bias. Traditional methods that analyze only the restudied patients fail to correct for the important confounding influence of the clinical status of the nonrestudied patients. By using this readily available clinical information about the nonrestudied patients, a predictive method may be developed that provides a closer estimate of the true restenosis behavior for the population as a whole.

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PubMed1993

Lesion-to-lesion independence of restenosis after treatment by conventional angioplasty, stenting, or directional atherectomy. Validation of lesion-based restenosis analysis.

BACKGROUND: Since many restenosis trials include patients in whom more than one lesion is treated, analysis of the angiographic data on a "per lesion" basis might be confounded by potential correlations of restenosis among multiple treated lesions within each patient. The goals of this study were: 1) to determine whether there was any correlation in the rate of restenosis among multiple lesions that underwent conventional angioplasty, stenting, or directional atherectomy within the same patient and 2) to determine whether lesions treated in a multilesion intervention experience a different magnitude of restenosis than lesions undergoing single-lesion procedures. METHODS AND RESULTS: Of 441 patients treated by Palmaz-Schatz stenting (n = 114), directional atherectomy (n = 100), or conventional balloon angioplasty (n = 227), 67 underwent multilesion procedures involving treatment of 146 lesions. A general linear model with intraclass correlation (GLIMIC) was used to calculate the coefficient of correlation (rho) of the change in the measured minimum luminal diameter (late loss) from the time of the initial procedure to 6-month angiogram among the multiple lesions within the same patient for all 441 patients. This showed no correlation among multiple lesions within the same patient for the late loss in minimum luminal diameter (rho = -0.12 [95% CI: -0.40, 0.12]), among lesions in the same vessel (rho = 0.14 [95% CI: -0.34, 0.62]), or among different vessels (rho = -0.18 [95% CI: -0.52, 0.16]), suggesting that the magnitude of late loss is independent among multiple lesions within the same patient. There was no difference (p = 0.96) between the observed incidence of zero-, one-, and two-vessel restenosis (> or = 50% diameter stenosis at follow-up) for patients with multiple-lesion treatment and that predicted assuming lesion-to-lesion independence. Similarly, there was no difference in late loss or in the overall binary restenosis rate when single-lesion procedures were compared with multilesion procedures. Multivariable analysis of the late loss in lumen diameter (which adjusted for the effects of the acute result and the device used) demonstrated no independent effect (p = 0.20) of single-lesion versus multilesion status. CONCLUSIONS: Luminal encroachment appears to occur at independent rates among multiple lesions treated in a single patient. The observed incidence of restenosis for patients with multiple treated lesions is accurately predicted assuming independent probabilities of restenosis. Lesion-based analysis, even when including multiple treated lesions within the same patient, is thus valid for evaluating conventional angioplasty, stenting, or directional atherectomy.

Angioplasty, Balloon, Coronary↗
PubMed1993

Accuracy of clinical examination in the evaluation of femoral false aneurysm and arteriovenous fistula.

A prospective study was undertaken to define the comparative value of physical examination versus duplex scanning in the detection of femoral false aneurysm and arteriovenous fistula after percutaneous femoral artery puncture. Fifty-three patients were referred to the vascular surgery service after femoral artery catheterization for evaluation of a groin hematoma or a new femoral bruit. All patients were evaluated initially by a vascular surgeon and then by duplex scan. The results of these evaluations were compared with the findings at operation. Physical examination was 100% sensitive and 100% specific in the diagnosis of arteriovenous fistula, whereas duplex scan achieved a sensitivity of only 58% and a specificity of 100%. Physical examination was 92% sensitive and 93% specific in the detection of femoral false aneurysm compared with a sensitivity of 83% and a specificity of 100% for duplex scanning. Physical examination is the best method for detecting and following patients with arteriovenous fistula. False aneurysms can be detected reliably by physical examination, although evaluation with a duplex scan is necessary to identify the precise size and anatomy of these lesions.

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PubMed1992

Predictors of long-term outcome after percutaneous balloon mitral valvuloplasty.

BACKGROUND: Percutaneous balloon mitral valvuloplasty is known to produce short-term hemodynamic and symptomatic improvement in many patients with mitral stenosis. Comprehensive assessment of the clinical usefulness of balloon valvuloplasty requires evaluation of patients' long-term outcomes. METHODS: We performed balloon mitral valvuloplasty in 146 patients between October 1, 1985, and October 1, 1991. Base-line demographic, clinical, echocardiographic, and hemodynamic variables were evaluated in order to identify predictors of long-term event-free survival. RESULTS: Balloon mitral valvuloplasty was completed successfully in 136 (93 percent) of the patients in whom the procedure was attempted; it resulted in an increase in the mean (+/- SD) mitral-valve area from 1.0 +/- 0.4 to 2.1 +/- 0.9 cm2 and a decrease in the mean transmitral pressure gradient from 14 +/- 5 to 6 +/- 3 mm Hg (P < 0.001 for both comparisons). The estimated overall five-year survival rate was 76 +/- 5 percent, and the estimated five-year event-free survival rate (the percentage of patients without mitral-valve replacement, repeat valvuloplasty, or death from cardiac causes) was 51 +/- 6 percent. According to multivariate Cox proportional-hazards analysis, the independent predictors of longer event-free survival were a lower mitral-valve echocardiographic score (a measure of mitral-valve deformity; range, 0 for a normal valve to 16 for a seriously deformed valve; P < 0.001), lower left ventricular end-diastolic pressure (P = 0.001), and a lower New York Heart Association (NYHA) functional class (P = 0.04). Patients with no risk factors for early restenosis or only one risk factor (echocardiographic score > 8, left ventricular end-diastolic pressure > 10 mm Hg, or NYHA functional class IV) had a predicted five-year event-free survival rate of 60 to 84 percent, whereas patients with two or three risk factors had a predicted five-year event-free survival rate of only 13 to 41 percent. CONCLUSIONS: Balloon mitral valvuloplasty as a treatment for selected patients with mitral stenosis has good long-term results. The long-term outcome after this procedure can be predicted on the basis of patients' base-line characteristics.

Catheterization↗
PubMed1992

Influence of vessel selection on the observed restenosis rate after endoluminal stenting or directional atherectomy.

In comparing the restenosis rates among different interventions, 1 potential confounder might be the differences in the vessels treated, as dictated by the technical limitations of particular devices. The purpose of this study was to use current "acute gain-late loss" analysis to examine what influence vessel selection has on the restenosis rates seen after coronary stenting or directional atherectomy. The minimal luminal diameter of native coronary lesions was measured before and immediately after intervention in 102 single Palmaz-Schatz stents and 347 atherectomies, 367 (82%) of which had repeat angiographic measurement 6 months after intervention. Atherectomy-treated lesions had a higher proportion of left anterior descending to right coronary arteries (68 vs 24%) compared with stents (31 vs 54%), p < 0.001. Although subsequent restenosis rates were similar for stenting (25%) and atherectomy (30%, p = 0.42), left anterior descending versus right coronary lesions had a significantly higher restenosis rate for the overall group (35 vs 18%, p = 0.009), for stents (44 vs 13%, p = 0.008) and for atherectomy (35 vs 22%, p = 0.10), respectively. Multivariable analysis demonstrated that postprocedure luminal diameter (p = 0.03, p = 0.009) and coronary location (the proportion of left anterior descending vessels treated, p = 0.002, p < 0.001), but not device type (stent vs atherectomy), were strong independent determinants of restenosis according to both binary (> 50% diameter stenosis) and continuous (late percent stenosis) definitions.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1992

Long-term results of directional coronary atherectomy: predictors of restenosis.

OBJECTIVES: This study was performed to obtain better understanding of the long-term clinical efficacy of directional coronary atherectomy. BACKGROUND: Although this procedure yields favorable acute results, its acceptance has been limited by the perception that late results (that is, freedom from restenosis) are no better than those of conventional angioplasty. METHODS: A total of 225 atherectomies performed in 190 patients between August 1988 and July 1991 were examined. Minimal lumen diameter of the treated segments was measured on angiograms obtained before, after and 6 months after intervention. RESULTS: Although most lesions (97%) had one or more characteristics predictive of unfavorable short- or long-term results after conventional angioplasty, atherectomy was successful in 205 lesions (91%) with a mean residual stenosis of 7 +/- 16%. After subsequent balloon angioplasty in 16 unsuccessful atherectomy attempts, procedural success was 98%. There were no deaths or Q wave myocardial infarctions, and one patient (0.5%) underwent emergency bypass surgery. Six-month angiographic follow-up was obtained in 77% of the eligible patients. The overall angiographic restenosis rate was 32%. Predictors of a lower restenosis rate included a postprocedure lumen diameter > 3 mm (24% vs. 39%, p = 0.047), serum cholesterol < or = 200 mg/dl (18% vs. 40%, p = 0.018) and recent myocardial infarction (16% vs. 37%, p = 0.034). Life-table analysis showed a 2% mortality rate and a 26% incidence of other events (myocardial infarction, repeat revascularization) within the 1st year. The annual 5% mortality rate and 7% incidence of other events during years 2 and 3 were related in large part to the existence or progression of disease at other locations. CONCLUSIONS: Six-month angiographic follow-up of patients who underwent directional coronary atherectomy during the 1st 3 years of our experience shows an overall restenosis rate of 32%, with lower rates in patients with a postatherectomy lumen diameter > or = 3 mm, cholesterol level < or = 200 mg/dl or a recent myocardial infarction. Few if any events relating to the site of atherectomy developed after the 1st year of follow-up.

Atherectomy, Coronary↗
PubMed1992

Acute and long-term outcome of narrowed saphenous venous grafts treated by endoluminal stenting and directional atherectomy.

Angioplasty of the narrowed saphenous vein bypass grafts remains a difficult challenge. Over a 37-month period at this institution, 119 of 176 interventions (68%) on saphenous vein grafts (average age 8.3 years from bypass surgery to graft intervention) were performed using either directional coronary atherectomy (n = 35) or Palmaz-Schatz intracoronary stents (n = 84), representing 37% of all stents and 15% of all atherectomies during the study period, respectively. Of the 57 saphenous vein graft lesions treated with conventional balloon angioplasty during this period, 49 (86%) had 1 or more contraindications to stenting or directional atherectomy (thrombus, total occlusion, reference vessel less than 3 mm in diameter). The acute success rate was 99% for stents (1 failure to dilate) and 94% for directional atherectomy (2 failures to cross the lesion with the atherectomy device). Lumen diameter increased from 0.9 to 3.6 mm (reference vessel 3.6) for stents, and from 0.9 to 3.5 mm (reference 3.8) for atherectomy (for all comparisons, p = not significant), with no major complications (abrupt or subabrupt closure, emergent coronary bypass surgery, death, or Q-wave myocardial infarctions). During the same time period 50 of 57 vein grafts (88%) rejected for stenting or atherectomy were dilated successfully by conventional balloon angioplasty, with 3 patients (5%) requiring emergent coronary bypass surgery. Angiographic follow-up was available for 50 of 64 eligible patients (78%).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Frequency and outcome of chest pain after two new coronary interventions (atherectomy and stenting).

Between June 1988 and July 1991, 464 new device interventions (Palmaz-Schatz stent or Simpson directional atherectomy) were performed in 410 patients. Chest pain occurred within 72 hours after the procedure in 94 patients (23%). All patients were evaluated with electrocardiograms and cardiac isoenzymes on the day after the procedure, and urgent repeat coronary angiography was performed in 29 chest pain patients (31%). Whereas all 14 patients with abnormal findings on repeat angiography had electrocardiographic changes, 6 of the 20 restudied patients (30%) with electrocardiographic changes had no angiographic explanation for chest pain. Non-Q-wave myocardial infarction occurred in 22 patients (5%) (10 of 35 [29%] with chest pain and electrocardiographic changes, 3 of 44 [7%] with chest pain and no electrocardiographic change, and 9 of 316 [3%] without chest pain). Factors associated with chest pain after new device intervention included a decreased residual percent stenosis (p = 0.05), incomplete revascularization (p = 0.005) and the presence of multivessel disease (p = 0.001). Vessel dissection after stenting but not atherectomy was associated with postprocedure chest pain. Chest pain is common (23%) after new device intervention. Electrocardiographic changes are a sensitive marker of angiographic abnormality and confer a higher risk of non-Q-wave myocardial infarction, but no increase of in-hospital mortality. Determinants of postprocedure chest pain are lower residual percent stenosis, incomplete revascularization and the presence of multivessel disease. Patients with chest pain but no electrocardiographic changes early after successful stent placement or atherectomy need not routinely undergo urgent recatheterization.

Angina Pectoris↗
PubMed1992

Role of superficial femoral artery puncture in the development of pseudoaneurysm and arteriovenous fistula complicating percutaneous transfemoral cardiac catheterization.

Of 13,203 transfemoral diagnostic and therapeutic cardiac catheterization procedures performed between January 1, 1980 and December 31, 1990, 73 (0.55%) were complicated by pseudoaneurysm (PA) formation, and 15 (0.11%) by arteriovenous fistulas (AVF). The rate of PA increased progressively from 0.44% (1980-1987), to 0.59% (1987-1989), to 0.92% (1990), with no corresponding change in the incidence of AVF. The rising incidence of PA complicating transfemoral cardiac catheterization was associated closely with the use of larger diameter catheters and aggressive antiocoagulation during coronary interventions, but findings during surgical repair suggested that puncture of the superficial femoral (SFA), rather than the common femoral artery (CFA), was an important avoidable cause of some PA and AVF. A technique for fluoroscopic localization of the puncture site to avoid inadvertent SFA puncture and the associated increased risk of complication is proposed.

Aneurysm↗
PubMed1992

Coronary arteriovenous fistula presenting as congestive heart failure.

Coronary arteriovenous fistulae are rare, but can be of hemodynamic significance. We report a circumflex-coronary sinus fistula in an elderly man which was associated with a loud continuous murmur and congestive heart failure. Noninvasive evaluation, including transesophageal echocardiography and magnetic resonance imaging, suggested the diagnosis. Angiographic diagnosis of concomitant atherosclerotic coronary disease may be difficult, and can require postoperative study.

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