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Biomedical subjects

D S Baim

Publications and source records attributed to D S Baim.

At least 145 records · Page 8Linked to original sources
PubMed1992

Changing incidence and management of abrupt closure following coronary intervention in the new device era.

Abrupt closure of the dilated segment occurs in approximately 4 to 7% of cases following conventional percutaneous coronary angioplasty. Additional balloon angioplasty reverses roughly 40% of these closures, to yield an overall 1.6 to 3.4% rate of emergent surgery. The impact of new devices on the incidence and reversal rate of abrupt closure has not been examined. Abrupt closure occurred in 80 (4.2%) of 1,919 consecutive coronary angioplasties performed in our single center, 389 (20%) of which were performed using newer interventions (208 Palmaz-Schatz stents, 170 directional coronary atherectomies, and 11 elective laser balloon angioplasties). Abrupt closure was less frequent following newer coronary interventions (1.8%) compared to standard balloon angioplasty (4.9%, P < 0.01), possibly reflecting case selection. When abrupt closure did occur, percutaneous rescue was successful in 53 (66%) patients, including 42 (53%) who were rescued using standard or perfusion balloon angioplasty, and 11 (13%) who were rescued using laser balloon balloon angioplasty after failure of additional angioplasty attempts. Medical therapy alone was used in 8 (10%), while emergent coronary bypass surgery was performed in 18 (23%), yielding an overall emergent surgery rate of 0.9%. Q-wave myocardial infarction was significantly less frequent (0.2%) following percutaneous rescue, compared to either medical therapy (25%) or emergent surgery (33%, P < 0.001). In our catheterization laboratory, use of these 3 new coronary interventional devices coincides with a trend towards a lower incidence of abrupt closure, a higher percutaneous rescue rate with reduced incidence of myocardial infarction, and a lower emergent bypass surgery rate.

Aged↗
PubMed1992

Histologic findings in specimens obtained by percutaneous directional coronary atherectomy.

Percutaneous directional coronary atherectomy is a second-generation, catheter-based technique for the treatment of coronary artery disease that provides a unique opportunity to study tissue obtained from coronary artery stenoses. We reviewed the histologic findings in 131 coronary atherectomy specimens from 116 patients, including 79 primary lesions and 52 restenosis lesions that developed after a prior coronary intervention. Although atherosclerotic plaque was seen in 95% of cases, an important observation was the finding of deep arterial wall components in the majority of patients, including media in 61% and adventitia in 31%. Despite the relatively common finding of deep wall components, this was not associated with acute clinical complications. Intimal hyperplasia was seen in 64% of cases, including 96% of restenosis lesions. However, intimal hyperplasia was also seen in 45% of primary lesions. The intimal hyperplasia in primary and restenosis lesions was histologically identical and was characterized by cells that showed staining for vimentin and muscle-specific actin, consistent with a myogenous and/or myofibroblastic phenotype. Restenosis was seen in 29 of 94 lesions (31%) with angiographic follow-up an average of 6.3 months after atherectomy. The risk of restenosis was not significantly related to the vessel treated, the nature of the lesion treated (ie, primary v restenosis lesion), or any of the histologic features evaluated. In conclusion, (1) deep arterial wall components are commonly observed in coronary atherectomy specimens without acute complications and (2) intimal hyperplasia is a sensitive, but not specific, marker for restenosis lesions.

Cardiology↗
PubMed1992

Transcatheter closure of coronary artery fistulas.

Transcatheter closure of a coronary artery fistula was undertaken in nine patients. There were three fistulas from the left circumflex coronary artery to the coronary sinus, three from the left anterior descending coronary artery to the right ventricular apex, two from the right coronary artery to the superior vena cava/right atrial junction and one fistula from the left circumflex artery to the pulmonary artery. The fistula was closed with Gianturco coils in six patients, a double-umbrella device in two and a combination of an umbrella and coils in one patient. All fistulas are completely occluded. Complications consisted of migration of two coils, one of which was retrieved, and a transient junctional tachycardia in one patient. In an additional three patients with multiple coronary artery fistulas, transcatheter occlusion was not attempted.

Adolescent↗
PubMed1992

Abrupt vessel closure after directional coronary atherectomy. The U.S. Directional Atherectomy Investigator Group.

From October 1, 1986 to December 31, 1989 directional coronary atherectomy was performed during 1,020 procedures (1,140 lesions) at 14 clinical centers. Abrupt vessel closure, defined as a total coronary occlusion or subtotal occlusion associated with clinical evidence of myocardial ischemia, occurred in 43 procedures (4.2%). It developed in the catheterization laboratory in 34 patients, but was delayed 1 to 96 h after directional atherectomy in 9 patients. By univariate analysis the incidence of abrupt closure was higher in directional atherectomy of de novo lesions (p less than 0.001), lesions in the right coronary artery (p = 0.001) and diffuse lesions (p = 0.04). The incidence of abrupt closure tended to be lower in directional atherectomy of saphenous vein grafts as opposed to native coronary arteries (1.6% vs. 4.4%; p = 0.08). Clinical findings during abrupt closure included severe angina in 26 patients, myocardial infarction in 17 patients, hypotension in 5 patients and death in 2 patients. Balloon angioplasty was attempted in 32 patients after abrupt vessel closure. In 16 patients balloon angioplasty resulted in initial resolution of the closure episode, although 1 patient died 96 h after the procedure. Fifteen of 16 patients without initial improvement after balloon angioplasty underwent coronary bypass operation; 9 additional patients with abrupt closure were referred directly for bypass operation. It is concluded that abrupt vessel closure develops relatively infrequently after directional coronary atherectomy. In the absence of severe coronary dissection, abrupt closure after directional atherectomy may be effectively managed with balloon angioplasty in some cases, although coronary bypass operation is often required.

Adult↗
PubMed1992

Novel approach to the analysis of restenosis after the use of three new coronary devices.

Restenosis after coronary intervention has remained a vexing problem despite the introduction of nearly 24 newer coronary interventional devices. To more clearly evaluate the potential impact of three such new devices on restenosis, coronary lumen diameters were measured before, immediately after and at 6 months after intervention, and restenosis was analyzed using continuous geometric techniques. Lumen diameters were measured before and immediately after intervention in 223 coronary vessels treated with one of three new devices: a single Palmaz-Schatz stent (n = 87), directional atherectomy (n = 125) and laser balloon angioplasty (n = 11); 184 (83%) of the patients underwent follow-up angiography 6 months after treatment. The immediate increase in lumen diameter produced by the intervention (acute gain) and the subsequent reduction in lumen diameter between the time of intervention to 6 month follow-up study (late loss) were examined. For each of the three interventions, the restenosis rate at follow-up study was analyzed using a traditional dichotomous definition (greater than or equal to 50% diameter stenosis), as well as a novel graphic technique. Although the apparent restenosis rates differed significantly among the three interventions (19% for stents, 31% for atherectomy and 50% for laser balloon angioplasty; p = 0.02), late loss among the three interventions was equivalent (average 1 mm; p = 0.91). There were, however, marked differences in the acute gain achieved by the three interventions: 2.6 mm for stents, 2.2 mm for atherectomy and 2 mm for laser balloon angioplasty; p less than 0.001). It was these differences in acute gain rather than late loss that explained the observed differences in restenosis rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Laser↗
PubMed1992

PTCA in the elderly: the "young-old" versus the "old-old".

OBJECTIVE: To evaluate the use of percutaneous transluminal coronary angioplasty (PTCA) in elderly coronary artery disease (CAD) patients. DESIGN: A prospective study of patients 60 years and older undergoing de novo PTCA. We analyze patient risk factors, underlying disease, and clinical outcomes, with at least 3-year follow-up. Comparisons between different age strata among these patients are made to clarify differences between the young old (60 to 69 years), the middle old (70 to 79 years), and the very old (80 years and older). SETTING: Beth Israel Hospital, Boston, both a primary care and tertiary care teaching hospital. PATIENTS: 907 consecutive elderly cardiac patients referred for PTCA are studied. INTERVENTIONS: PTCA's were completed using the newest catheter technologies as they became available. All patients were premedicated with aspirin and dipyridamole, and all were anticoagulated with heparin. RESULTS: Subdivision by age demonstrates that the majority (67%) of patients aged 60 to 69 were males, but females were preponderant (61%) in those aged 80 and older. Octogenarians also had lower incidence of hypercholesterolemia, tobacco use, and family history of CAD, and a higher frequency of CHF, angina, and previous MI. Although total procedure-complications increased with age, critical complications (MI, reocclusion, CABG, death) did not. Primary procedural success was similar in all age strata, but older patients had a higher prevalence of multi-vessel disease and longer hospital stay. Follow-up shows that most patients did well after PTCA; there was no increase in repeat PTCA, CABG, and MI with age. CONCLUSIONS: While advanced age is associated with changes in risk and clinical parameters for CAD patients, age alone is not a reasonable criterion to limit the use of PTCA.

Age Factors↗
PubMed1992

Coronary angioplasty performed within the thrombolysis in Myocardial Infarction II study.

BACKGROUND: Percutaneous transluminal coronary angioplasty (PTCA) of the infarct-related artery was performed within 42 days of recombinant tissue-type plasminogen activator (rt-PA) administration in 1,414 of the 3,534 patients who participated in the Thrombolysis In Myocardial Infarction (TIMI) II study. Primary angiographic success was obtained in 88.7%, with bypass surgery within 24 hours in 3.3% and death within 24 hours in 0.7% of patients. By 1 year, 25.1% of the 1,414 patients had sustained one or more adverse outcomes including death (3.6%), reinfarction (8.4%), or the need for further revascularization (20%). METHODS AND RESULTS: Despite these generally favorable results, multivariate testing identified several anatomic and clinical subgroups as having an increased risk ratio (RR) for adverse outcome: Unsuccessful PTCA was more common in patients undergoing protocol-assigned PTCA within 2 hours of rt-PA administration (RR, 2.7; p less than 0.001) and in patients over age 70 years (RR, 1.7; p = 0.034). The need for further revascularization within 1 year was increased in the 30.4% of patients with multivessel disease (RR, 2.5; p less than 0.001), patients with prior angina (RR, 1.4; p less than 0.006), or those undergoing ischemia-driven PTCA within 15 hours of rt-PA administration (RR, 1.7; p = 0.022). The risk of death or recurrent infarction within 1 year was increased by the presence of multivessel disease (RR, 1.6; p = 0.007) or prior angina (RR, 1.5; p = 0.014). CONCLUSIONS: These observations do not necessarily apply to patients undergoing primary PTCA (or PTCA after other thrombolytic agents); however, they do offer a unique yardstick against which to evaluate the results of PTCA in myocardial infarction.

Angioplasty, Balloon, Coronary↗
PubMed1992

Evidence implicating nonmuscle myosin in restenosis. Use of in situ hybridization to analyze human vascular lesions obtained by directional atherectomy.

BACKGROUND: Identification of genes that are specifically activated in restenosis lesions after percutaneous transluminal angioplasty represents a necessary step toward molecular manipulation designed to inhibit cellular proliferation responsible for such lesions. Whereas quiescent smooth muscle cells (contractile phenotype) preferentially express smooth muscle myosin, proliferating smooth muscle cells (synthetic phenotype) have been shown to preferentially express nonmuscle myosin in vitro. Accordingly, we analyzed the expression of a recently cloned isoform of human nonmuscle myosin heavy chain (MHC-B) in fresh human restenotic lesions. METHODS AND RESULTS: A total of 10 lesions, including four restenosis (three superficial femoral arterial lesions and one saphenous vein bypass lesion) and six primary (four superficial femoral arterial lesions and two coronary arterial lesions) obtained percutaneously by directional atherectomy, were processed for examination by in situ hybridization. In total, 150 tissue sections of restenotic lesions (66 sections), primary lesions (78 sections), and normal internal mammary artery (six sections) were hybridized with the nonmuscle MHC-B probe. Restenotic lesions showed intense hybridization to the nonmuscle MHC-B cRNA probe, as demonstrated by a clustering of more than 20 grains per cell nucleus in 80% of the cells examined within a high-power field (x250); in contrast, an equivalent degree of hybridization was observed in only 7% of cells within primary lesions (p less than 0.001). Results of immunocytochemistry using monoclonal antibody to smooth muscle actin indicated that cells demonstrating strong hybridization were smooth muscle in origin. CONCLUSIONS: These findings demonstrate that 1) human vascular tissue obtained by percutaneous directional atherectomy constitutes appropriate biopsy material for gene expression studies at the mRNA level, and 2) nonmuscle MHC-B mRNA is present in greater abundance among restenotic versus primary vascular stenoses. These observations thus provide a rational basis to explore restenotic lesions on a larger scale to identify genes that are activated in these lesions and establish potential targets for future gene therapy.

Arteriosclerosis↗
PubMed1992

Restenosis after directional coronary atherectomy. Effects of luminal diameter and deep wall excision.

BACKGROUND: Deep wall excision during directional atherectomy has been reported in one study to increase the risk of subsequent restenosis. On the other hand, we have observed that the probability of late (6-month) restenosis is reduced by maximizing postprocedure luminal diameter. Although such maximal luminal enlargement by directional atherectomy has not increased procedural complications in our experience, it might well increase the incidence of subintimal (deep wall component) recovery. We performed this study to evaluate the relative influences of luminal enlargement and deep wall component excision on postatherectomy restenosis. METHODS AND RESULTS: Atherectomy resulted in a 7 +/- 15% residual stenosis with < 0.5% incidence of angiographic vessel perforation. The minimal luminal diameter of each lesion was measured before and after intervention in 413 lesions, 389 (94%) of which had histological analysis of the excised specimens. Specimens were categorized by the deepest layer retrieved: type I (recovery of intima alone, n = 141), type II (recovery of media, n = 79), and type III (recovery of adventitia, n = 65). Repeat angiographic measurement of minimal luminal diameter was available for 329 (80%) segments 6 months after atherectomy. Compared with the 32% restenosis rate for type I excision, there was no increase in restenosis (stenosis > 50%) for type II, type III, or types II+III (p = 0.86). Stratification by vessel characteristics also failed to show any association between restenosis and deep wall component recovery in any subgroup, including native coronary (p = 0.85), left anterior descending coronary artery (p = 0.70), right coronary artery (p = 0.51), saphenous graft (p = 0.78), or prior restenosis lesions (p = 0.98). Paradoxically, the recovery of adventitia (type III excision) was associated with a lower late percent stenosis (p = 0.03) and a trend toward less restenosis (p = 0.11) compared with type I excisions. A multiple logistic regression model was constructed that demonstrated immediate postprocedure luminal diameter (p = 0.02) to be an independent determinant of restenosis. In this model, the presence of deep wall components (type II+III) did not adversely affect (p = 0.86) restenosis, but the recovery of adventitia was associated with an independent trend toward reduced restenosis (p = 0.06). CONCLUSIONS: The immediate goal of directional atherectomy should be to safely provide the largest lumen possible in order to reduce restenosis. The recovery of deep wall components does not appear to jeopardize the beneficial effect that obtaining a large immediate postprocedure lumen diameter has on reducing the incidence of late restenosis.

Atherectomy, Coronary↗
PubMed1992

The importance of acute luminal diameter in determining restenosis after coronary atherectomy or stenting.

BACKGROUND: We evaluated native coronary arteries treated by directional coronary atherectomy or balloon-expandable stent placement in an effort to derive a quantitative geometric model relating the luminal diameter immediately after intervention to that present 6 months later. The minimal luminal diameter of each lesion was measured before and immediately after intervention in 102 single Palmaz-Schatz stents and 134 directional atherectomies, 192 (81%) of which had repeat angiographic measurement of minimal luminal diameter 6 months after the intervention. The immediate enlargement in luminal diameter produced by the intervention (acute gain) and the subsequent reduction in luminal diameter from the time of intervention to 6 months of follow-up (late loss) were calculated. METHODS AND RESULTS: Luminal diameter increased from 0.69 +/- 0.40 mm to 3.11 +/- 0.64 mm (acute gain, 2.41 +/- 0.64 mm) after intervention, providing an immediate postprocedure residual stenosis of 1 +/- 14% relative to a reference diameter of 3.13 +/- 0.65 mm. At 6-month follow-up, the late luminal diameter was 1.97 +/- 0.92 mm (late loss, 1.13 +/- 0.89 mm), yielding a late diameter stenosis of 36 +/- 26%. The restenosis rate (according to the traditional definition of diameter stenosis > or = 50%) was 30%. Multivariable analysis demonstrated that late luminal diameter (p = 0.02), late percent stenosis (p = 0.04), and restenosis (according to a > 50% definition, p = 0.04) were each strongly associated with the luminal diameter present immediately after the procedure. Whereas late luminal diameter was also influenced by reference artery size and the vessel treated (left anterior descending versus right coronary artery), reference vessel size was rejected by the multivariable models of late percent stenosis and binary restenosis after they were adjusted for the effect of postprocedure luminal diameter. Once adjusted for postprocedure luminal diameter, neither late luminal diameter nor late loss was found to be independently determined by which device was used (atherectomy versus stents). Rather, late loss was determined independently by the immediate postprocedure luminal diameter (p = 0.005) and the postprocedure percent stenosis (p = 0.02). Although late loss thus increased with acute gain, the net beneficial effect of increased acute gain was maintained: Late loss was only a fraction (0.47) of acute gain, so the ability of a larger postprocedure luminal diameter to reduce the probability of subsequent restenosis was preserved. CONCLUSIONS: This quantitative model demonstrates that the late coronary lumen diameter and the probability of restenosis after Palmaz-Schatz stenting or directional atherectomy are influenced strongly by the lumen diameter present immediately after the procedure rather than by the specific device used. Although the influence of a larger acute result on reduced restenosis appears to be well established in this treatment population, the interplay among the multiple other biological influences on restenosis limits the ability to predict the probability of restenosis for the individual patient based on a large acute result alone. Future studies of restenosis, however, can further refine this multivariable quantitative model by adjusting for the effects of other clinical variables, mechanical interventions, or drug therapies in addition to the clear effect of postprocedure luminal diameter.

Atherectomy, Coronary↗
PubMed1992

Restenosis after placement of Palmaz-Schatz stents in native coronary arteries. Initial results of a multicenter experience.

BACKGROUND: Several metallic intracoronary stents are currently undergoing preliminary evaluation to ascertain potential benefit as means to reduce the 30-40% incidence of restenosis after balloon angioplasty. METHODS AND RESULTS: To determine the incidence and correlates of restenosis after placement of Palmaz-Schatz stents in native coronary arteries in the first group of patients selected for this procedure, clinical and quantitative angiographic data from 206 consecutive patients (221 stenoses) with successful stent placement (diameter stenosis < 50%) were analyzed. Six patients (2.9%) had thrombosis-mediated stent closure within 1 month after stent placement and were excluded from long-term angiographic follow-up. One hundred eighty-one (91%) of the remaining 200 patients had angiography at 5.8 +/- 2.1 months. Patients with and without follow-up did not differ in any baseline characteristic; in particular, history of restenosis at the site stented (73% versus 65%), placement of multiple overlapping stents (17% versus 20%), and mean poststent diameter stenosis (16 +/- 12% versus 14 +/- 12%). The overall incidence of restenosis (diameter stenosis > or = 50% at follow-up) in this group at high risk for restenosis was 36% (95% confidence interval, 29-43%) on a per-stenosis basis. The incidence of restenosis when a single stent was placed was 30% (95% confidence interval, 23-37%). Risk was dependent upon a history of restenosis (present versus absent 36% versus 16%, p = 0.02) and upon whether or not a poststent stenosis < or = 0% was achieved (6% versus 33%, p = 0.02). When multiple overlapping stents were placed, restenosis occurred at 64% of sites, and placement of multiple stents was discouraged during the later phases of this study as these results became apparent. CONCLUSIONS: Although multiple stents appear to yield a poor long-term result, placement of single stents may offer a benefit compared with standard coronary angioplasty, particularly if an excellent angiographic result can be obtained in patients without prior restenosis. Further randomized trials in such patients are needed.

Coronary Angiography↗
PubMed1991

Salvage of branch vessels during bifurcation lesion angioplasty: acute and long-term follow-up.

To evaluate angiographic success, frequency of branch vessel loss and salvage, and long-term outcome, we studied the early and late outcomes of 56 consecutive patients who underwent PTCA of bifurcation lesions, which involved the left anterior descending or left circumflex coronary artery, with stenoses greater than 70% in both the parent and an involved branch vessel. In 35 patients (63%), the PTCA strategy was attempted dilation of both the main vessel and the involved branch vessels using predominantly a double-wire, sequential balloon technique; in 21 (27%) the PTCA attempt was confined to the main vessel alone. Transient angiographic occlusion of the branch vessel occurred in 32% of patients in whom dilation of both vessels was attempted, and in 38% in whom the main vessel alone was dilated (p = NS); 91% of the occluded branch vessels were the salvaged when sequential angioplasty of both vessels had been initially planned, compared to only 38% when the initial strategy had been dilation of the main vessel alone (p less than .05). Predischarge exercise testing showed residual ischemia in 6% of patients who had both vessels successfully dilated, versus 37% in those in whom dilatation was confined to the main vessels (p less than .01). Clinical restenosis, defined as late (greater than 6 weeks) recurrence of angina or a positive exercise test, occurred in 42% of patients who had both vessels successfully dilated. Thus although bifurcation lesion angioplasty frequently results in transient branch vessel loss, these branches can usually be salvaged using a double-wire technique but tend to have a higher late restenosis than conventional single vessel PTCA.

Angioplasty, Balloon, Coronary↗
PubMed1991

A new technique for sheathless percutaneous intraaortic balloon catheter insertion.

Intraaortic balloon counterpulsation is helpful for controlling myocardial ischemia and providing hemodynamic support, but its applicability is limited by lower extremity ischemic complications in a significant percentage of patients. We developed a new sheathless technique for percutaneous intraaortic balloon catheter insertion which reduces the effective catheter diameter. A pilot study using this new technique resulted in a 10% rate of limb ischemia, without compromise of balloon function. We conclude that this technique may be useful in reducing the incidence of limb ischemia associated with intraaortic balloon counterpulsation.

Aged↗
PubMed1991

The NACI Registry: an instrument for the evaluation of new approaches to coronary intervention. The NACI Investigators.

The New Approaches to Coronary Intervention (NACI) Registry was developed to collect in-depth data about patients whose coronary artery lesions are being treated with new interventional techniques such as atherectomy, stents, and laser devices. The NACI Registry database distinguishes among several possible "modes" for device use, such as preparatory, planned definitive, and bailout use. Common definitions are used for data collection across all devices, and device-specific forms are used to record procedural details. NACI's unique modular form design facilitates thorough data collection, even for the most complex treatment scenarios. The database structure allows for data analysis at the patient, procedure, lesion, and device levels, as required to perform in-depth analyses of the immediate and long-term success of new devices. Once adequate knowledge of basic device performance has been collected, the Registry structure can also allow expeditious planning and performance of randomized trials comparing a new device to conventional PTCA.

Angioplasty, Balloon, Coronary↗