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Biomedical subjects

P L Whitlow

Publications and source records attributed to P L Whitlow.

At least 37 records · Page 2Linked to original sources
PubMed1997

Comparison of patients with either < 70% diameter narrowing or > or = 70% narrowing of the right coronary artery when performing rotational atherectomy on > or = 1 narrowing in the left coronary arteries.

This study compares the complication rates of patients undergoing rotational atherectomy of the left coronary system who had either minimal or significant narrowing of the right coronary artery (RCA). A series of 1,872 patients from a multicenter registry who were treated for left coronary artery disease were divided into <70% diameter stenosis (mild) and > or = 70% stenosis (severe) of the RCA. The patient demographics, lesion characteristics, and frequency of procedural complications for each group were compared. Of the 1,872 patients undergoing rotational atherectomy of the left coronary system, 86.3% (n = 1,616) had mild RCA disease and 13.7% (n = 256) had severe RCA disease. Comparing the mild and severe groups, death (0.8% vs 3.1%, p <0.005), non-Q-wave myocardial infarction (5.1% vs 8.6%, p <0.04), and bypass surgery (2.7% vs 5.8%, p <0.02) were increased in the severe group. Within the severe group, 7 of 8 deaths were in the 128 patients with total occlusion of the RCA. Multivariate analysis demonstrated that RCA stenosis increases the risk of death by 4.9, bypass surgery by 2.6, and non-Q-wave myocardial infarction by 1.8. Patients treated for left coronary disease who have > or = 70% stenosis of the RCA have increased complications during rotational atherectomy.

Atherectomy, Coronary↗
PubMed1996

Significance of mild transient release of creatine kinase-MB fraction after percutaneous coronary interventions.

BACKGROUND: The clinical significance of minor elevations in creatine kinase-myocardial band isoenzyme (CK-MB) after coronary interventions has not been systematically evaluated. METHODS AND RESULTS: We examined 4484 patients who underwent successful percutaneous transluminal coronary angioplasty or directional coronary atherectomy and whose peak CK levels did not exceed twice the upper limit of laboratory normal. Group 1 (3776 patients) had no CK or MB elevation after the procedure (ie, CK < or = 180 IU/L, with MB fraction < or = 4%). Group 2 (450 patients) had a peak CK level between 100 and 180 IU/L, with MB fraction > 4%, and group 3 (258 patients) had a peak CK level between 181 and 360 IU/L, with MB fraction > 4%. The strongest correlate of postprocedure CK-MB elevation was the performance of directional coronary atherectomy (odds ratio, 4.1; P < .0001), followed by the development of > or = 1 in-1ab minor procedural complication (odds ratio, 2.6; P < .0001). Clinical follow-up was available in 4461 patients (99.5%), with a mean duration of 36 +/- 22 months. Survival analysis, adjusted with Cox proportional hazards regression model, showed that the groups with elevated CK-MB had a significantly higher incidence of cardiac death (risk ratio, 1.3; P = .04) and myocardial infarction (risk ratio, 1.3; P = .03). Major ischemic complications (death, myocardial infarction, and coronary revascularization) occurred more frequently in the groups with increased CK-MB (groups 1 versus 2 versus 3, 37.3% versus 43.3% versus 48.9%; P = .01). CONCLUSIONS: This study shows that minor elevations of CK-MB after successful coronary interventions identify a population with a worse long-term prognosis compared with patients with no enzyme elevations and appear to have an adverse effect on long-term prognosis. Future studies of percutaneous coronary revascularization should include routine measurements of biochemical cardiac markers as important predictors of long-term prognosis.

Angioplasty, Balloon, Coronary↗
PubMed1996

The dilemma of diagnosing coronary calcification: angiography versus intravascular ultrasound.

OBJECTIVES: We sought to determine whether careful examination of angiograms in conjunction with other clinical information could reliably detect, quantitate and localize target lesion calcification before a coronary intervention. BACKGROUND: The presence, extent and location of calcium in coronary artery lesions are important determinants of outcome after coronary intervention. Intravascular ultrasound is proposed as a superior technique for identifying patients with coronary artery calcification. However, the precise role of this costly and invasive method has not yet been established. METHODS: Target lesion calcification was assessed in 183 patients (155 men; mean [+/-SD] age 58 +/- 10 years) by angiography and intravascular ultrasound before a planned percutaneous coronary intervention. RESULTS: Ultrasound detected calcium in 138 patients (>90 degrees in 56, 91 degrees to 180 degrees in 52, 181 degrees to 270 degrees in 22 and > 270 degrees in 8), whereas angiography showed calcification in 63 (1+ in 32, 2+ in 27 and 3+ in 4). The two techniques agreed in 92 patients and disagreed in 91. Sensitivity and specificity of angiography were 40% and 82%, respectively. The arc of calcium by ultrasound was greater in patients with angiographically visible calcification (175 degrees +/- 85 degrees vs. 108 degrees +/- 71 degrees, p=0.0001). The depth of calcification by ultrasound was superficial in 61 patients (44%), deep in 68 (49%) and mixed in 8 (7%). The sensitivity of angiography in identifying superficial calcium was 35%. Of 120 patients without angiographically visible calcium at the target lesion site, 83 showed calcium by ultrasound. The only predictor of ultrasound calcium in these 120 patients was angiographic calcification elsewhere in the coronary tree (p=0.0001). The probability of any calcium and superficial >90 degrees calcium were 60% and 12%, respectively, in the 90 patients without angiographic calcifications anywhere in the coronary tree. CONCLUSIONS: Despite poor sensitivity, angiography may help identify patients requiring intravascular ultrasound. When it is angiographically visible, the arc of calcium is likely to be large and superficial. Angiographic calcification at a remote site is a predictor of angiographically undetected target lesion calcium. Patients without angiographic calcification in the coronary tree may not need routine ultrasound examination, as the likelihood of >90 degrees superficial calcium is low.

Aged↗
PubMed1996

Femoral artery hemostasis using an implantable device (Angio-Seal) after coronary angioplasty.

Coronary catheter interventional procedures are associated with risk of access site complications. We report our experience with Angio-Seal, an implantable hemostasis device, when used in the femoral artery after coronary angioplasty procedures. Sixty-eight patients were studied. Their average age was 63 years; 84% of the patients were male. All had 8 French access sheaths and received bolus heparin (mean dose 12,690 U). The arterial sheaths were removed an average of 455 min after the conclusion of the procedure, when the activated clotting time was 220 +/- 94 sec (range 97-503 sec). The hemostasis device was successfully deployed in 63 patients (93%). The average time to achieve complete arterial hemostasis was 4.4 +/- 8.9 min (range 0-45). Immediate, total hemostasis without requiring any form of external pressure was obtained in 37 of these patients (54%). the incidence of complications was as follows: significant bleeding occurred in 9 patients (13%); there were 2 hematomas (3%); there were no vascular or infectious complications. One device embolization occurred when the connecting suture broke and the intravascular anchor was lost; no clinical sequelae resulted, and manual hemostasis was successful. In four other patients, the device did not deploy and was removed entirely, followed by uneventful manual hemostasis. Follow-up for 2 months revealed no late sequelae in any patient, and complete absorption of the device was documented by ultrasound study in all cases. We conclude that this implantable device can achieve arterial hemostasis quickly and safety when used in anticoagulated patients after coronary interventional procedures.

Aged↗
PubMed1996

Recanalization of Chronically Occluded Aortocoronary Saphenous Vein Bypass Grafts With Long-Term, Low Dose Direct Infusion of Urokinase (ROBUST): a serial trial.

OBJECTIVES: This multicenter study sought to evaluate the short-term efficacy and safety of prolonged, low dose, direct urokinase infusion in recanalization of chronically occluded saphenous vein bypass grafts in a large sample of patients, as well as to determine the 6-month patency rates for this procedure. BACKGROUND: Patients with chronically occluded aortocoronary vein grafts and uncontrolled angina pectoris have limited options for therapy. Previous work has shown that chronically occluded vein grafts can be recanalized by thrombolysis. METHODS: A coaxial infusion of urokinase (100,000 U/h) was given directly into occluded vein grafts in 107 patients. Balloon angioplasty was performed after lysis was achieved. Patients were discharged with warfarin and aspirin therapy. Six-month clinical follow-up data were obtained, and repeat angiography was encouraged. RESULTS: Initial patency was achieved in 74 patients (69%). Mean duration of infusion was 25.4 h, and mean urokinase dosage was 3.70 million U. Acute adverse events included acute myocardial infarction in 5 patients (5%), enzyme level elevation in 18 (17%), emergency coronary artery bypass graft surgery in 4 (4%), stroke in 3 (3%) and death in 7 (6.5%). Recanalization was unsuccessful in all seven patients who died. Six-month follow-up angiograms were obtained for 40 patients (54%), 16 of whom maintained a patent graft (40%). Angina was present in 13 patients with successful (22%) and 12 with unsuccessful (71%) recanalization at 6-month follow-up. CONCLUSIONS: Chronically occluded aortocoronary vein grafts can be recanalized in approximately 70% of appropriately selected patients. Complications are similar to those observed with repeat operations. Clinical follow-up shows an improvement in angina. This procedure is intended for patients with only one occluded vein graft. Strict adherence to the protocol will improve patency and reduce complications.

Angioplasty, Balloon, Coronary↗
PubMed1996

Defining the appropriate threshold of creatine kinase elevation after percutaneous coronary interventions.

The threshold of creatine kinase elevation after coronary interventions has been set at levels ranging in different studies from 2 to > 5 times the laboratory's upper limit of normal. This high variability is caused by the absence of any systematic evaluation of the prognostic implications of cardiac-enzyme elevation in this setting. This study was undertaken to evaluate the clinical, morphologic, and procedural correlates, and the long-term follow-up of two commonly used thresholds of creatine kinase (CK) elevation after successful percutaneous coronary interventions, in an attempt to define the level of postprocedural cardiac enzymes that correlates with adverse clinical outcome. We examined 4664 consecutive patients who underwent successful coronary angioplasty or directional atherectomy at the Cleveland Clinic. Group I (4480 patients) had CK > or = 2 times control levels after the procedure (i.e., < or = 360 IU/L). Group II (123 patients) had a peak level between 361 and 900 IU/L, and group III (61 patients) had a peak level >900 IU/L with positive myocardial isoenzymes (CK-MB > 4%). Elevation of cardiac enzymes was associated with distinct clinical, morphologic, and procedural characteristics, including coronary embolism, recent infarction, transient in-laboratory closure, hemodynamic instability, vein graft procedures, and large dissections. Clinical follow-up was available in 4644 (99.6%) patients, with a mean follow-up of 36 +/- 22 months. Kaplan-Meier survival analysis adjusted with Cox proportional hazards regression model showed that cardiac-enzyme elevation was an important correlate of cardiac death (risk ratio, 2.19; p < 0.0001). The groups with elevated cardiac enzymes had a higher incidence of cardiac death compared with group I (p < 0.0001). There was also a trend toward more cardiac hospitalizations in the same groups (p = 0.15). The incidence of cardiac death and cardiac hospitalization on follow-up was not different between groups II and III, This study shows that CK elevations between 2 and 5 times control values after successful coronary interventions are associated with an adverse long-term outcome. The findings suggest that an appropriate CK threshold that has prognostic implications would be twice the upper limit of normal.

Angioplasty, Balloon, Coronary↗
PubMed1996

Decreased free radical scavengers with reperfusion after coronary angioplasty in patients with acute myocardial infarction.

Early reperfusion after myocardial infarction improves survival rate and is thought to preserve myocardial function, but the reperfusion of ischemic tissue may release oxygen free radicals, which could adversely affect left ventricular function and diminish the beneficial effects of reperfusion. Measurements related to free radical scavenging (plasma and erythrocyte enzyme systems, which are involved in free radical control, alpha-tocopherol, selenium, and manganese superoxide dismutase) may be indirect markers of free radical production. We evaluated 10 patients undergoing coronary angioplasty within 4 hours of myocardial infarction to measure the impact of abrupt reperfusion on free radical scavenger-related indexes. Pulmonary artery samples were taken before, immediately after, and 3 hours after angioplasty. During reperfusion, significant reductions occurred in alpha-tocopherol (1.1 +/- 0.3 mg/dl before, 0.9 +/- 0.2 mg/dl immediately after [p = 0.03], and 0.8 +/- 0.2 mg/dl 3 hours after percutaneous transluminal coronary angioplasty [p = 0.02]), and selenium levels (13.7 +/- 2.4 micrograms/dl before, 12.9 +/- 2.4 micrograms/dl immediately after, and 10.2 +/- 3.0 micrograms/dl 3 hours after angioplasty [p = 0.0006]). Erythrocyte markers (glutathione peroxidase and superoxide dismutase) were not altered by reperfusion, possibly reflecting the relatively long half-life of the erythrocyte. The erythrocyte glutathione peroxidase value before reperfusion in patients (30.8 +/- 5.1 IU/gm of hemoglobin) was lower than in a control group (36.1 +/- 6.5 IU/gm of hemoglobin; p = 0.01). Thus the decrease in plasma alpha-tocopherol and selenium after reperfusion in this group of patients may reflect a general alteration in plasma free radical scavenger levels, suggesting consumption of plasma free radical scavengers with reperfusion after acute myocardial infarction.

Angioplasty, Balloon, Coronary↗
PubMed1996

Role of intimal hyperplasia and arterial remodeling after balloon angioplasty: an experimental study in the atherosclerotic rabbit model.

The arterial response to injury appears to be an important factor in the development or restenosis. Traditionally, intimal hyperplasia has been thought to be the primary mechanism responsible for restenosis. However, recent studies have found that arterial remodeling is a major determinant of lumen loss after balloon angioplasty. In this study, we evaluated the actual separate contributions of intimal hyperplasia and arterial remodeling to the restenotic process after balloon angioplasty in the atherosclerotic rabbit model. One month after induction of focal atherosclerotic lesions, femoral arteries were randomized to receive treatment with either two or six balloon inflations. One group of rabbits was euthanized immediately after angioplasty to evaluate the initial degree of injury with each dilation strategy ("acute group"), and the rest were euthanized 28 days after angioplasty ("chronic group"). Arteries that had been treated with six inflations had a higher injury score than those treated with two (4.0+/-3.0 versus 1.9+/-1.5, P<.05). In the chronic group, there was a significant increase in intimal area in the six inflation-treated arteries compared with the two-inflation group (0.617+/-0.06 versus 0.432+/-0.05 mm2, P<.004). However, there was no significant difference in lumen cross-sectional area between groups. By multivariate analysis, the most important independent predictor of lumen area was the external elastic lamina (EEL) area, although the degree of intimal thickening was also a significant independent predictor. There was a strong, positive correlation between intimal area and EEL area: the larger the intimal area, the larger the EEL area (r=.703, P<.0001). The intimal area was similar in both restenotic and nonrestenotic lesions. In contrast, EEL area was significantly larger (due to remodeling) in nonrestenotic lesions. This study confirms previous findings that the degree of injury determines the degree of neointimal proliferation and supports recent findings that chronic arterial remodeling plays a major role in the final lumen area. Understanding and controlling the remodeling process rather than concentrating solely on intimal hyperplasia may yield better results after balloon angioplasty in the future.

Angioplasty, Balloon↗
PubMed1996

Incremental value of intravascular ultrasound during rotational coronary atherectomy.

During the last several years, major improvements in intravascular ultrasound image quality have led to new and important information about the clinical application of rotational atherectomy. Ultrasound is providing data on the mechanism of luman enlargement, burr sizing, and the effects of the procedure on different plaque morphologies. This information is often important for optimizing device selection and procedural success, as well as for minimizing complications. In this review we first discuss the currently available data regarding the mechanisms of lumen enlargement following rotational ablation and the implications of these findings for lesion and patient selection. We review how this data is modifying several of the technical aspects of the rotational ablation procedure in the interventional laboratory. We than assess the available data that suggest that preprocedural ultrasound examination may eventually help to identify lesions at high risk for adverse outcome with stand-alone balloon angioplasty or stent placement. These ultrasound data may help triage many of these targets to initial debulking with rotational ablation. Finally, we review data that suggest that ultrasound analysis has important implications for comparative trials of new devices, particularly trials of the Rotabalator.

Atherectomy, Coronary↗
PubMed1995

Long-term outcome of transient, uncomplicated in-laboratory coronary artery closure.

BACKGROUND: Successful reversal of abrupt vessel closure without resultant major ischemic complications (death, Q-wave myocardial infarction, or coronary artery bypass graft surgery) is achieved in nearly half of all cases of abrupt vessel closure. The long-term outcome of these patients has not been previously addressed, and it is not clear whether they have a different prognosis than that of patients who have a successful procedure not associated with transient vessel closure. METHODS AND RESULTS: We examined 4863 consecutive patients who underwent successful percutaneous transluminal coronary angioplasty (PTCA) or directional coronary atherectomy (DCA). Eighty-eight patients had an uncomplicated, successfully reversed transient in-laboratory vessel closure (group 2) and were compared with 4775 patients who had a successful procedure not associated with transient in-laboratory closure (group 1). Clinical follow-up was available in 4839 patients (99.5%), with a mean duration of 41 +/- 23 months (range, 1 to 104 months). Survival analysis showed that successfully treated, uncomplicated transient vessel closure per se does not have an adverse effect on long-term prognosis (death, myocardial infarction, or coronary interventions). However, when the procedure (PTCA or DCA) was associated with an increase in creatine kinase-MB (CK-MB), there was a significant adverse effect on long-term outcome. By multivariate logistic regression, an increase in postprocedure CK-MB was the most significant correlate for cardiac death (risk ratio, 1.25; P < .0001). An increase in CK-MB was also the most important correlate for major ischemic complications (death, infarction, or coronary interventions) on follow-up (risk ratio, 1.08; P = .0005). CONCLUSIONS: Transient, uncomplicated in-laboratory vessel closure per se does not have an adverse long-term effect. However, a concomitant elevation of postprocedure cardiac enzymes has an important and significant adverse effect on long-term outcome. This study suggests that periprocedural creatine kinase isoenzyme determination in patients experiencing in-laboratory coronary closure has important prognostic implications.

Angioplasty, Balloon, Coronary↗
PubMed1995

A multicenter, randomized trial of coronary angioplasty versus directional atherectomy for patients with saphenous vein bypass graft lesions. CAVEAT-II Investigators.

BACKGROUND: Directional coronary atherectomy and percutaneous transluminal coronary angioplasty have both been used in symptomatic patients with coronary saphenous vein bypass graft stenoses. The relative merits of plaque excision and removal versus balloon dilatation remain uncertain. We compared outcomes after directional coronary atherectomy or angioplasty in patients with de novo bypass graft stenoses. METHODS AND RESULTS: Fifty-four North American and European sites randomized 305 patients with de novo vein graft lesions to atherectomy (n = 149) or angioplasty (n = 156). Quantitative coronary angiography at a core laboratory assessed initial and 6-month results. Initial angiographic success was greater with atherectomy (89.2% versus 79.0%), as was initial luminal gain (1.45 versus 1.12 mm, P < .001). Distal embolization was increased with atherectomy (P = .012), and a trend was shown toward more non-Q-wave myocardial infarction (P = .09). Although the 6-month net minimum luminal diameter gain was 0.68 mm for atherectomy and 0.50 mm for angioplasty, the restenosis rates were similar, 45.6% for atherectomy and 50.5% for angioplasty (P = .491). At 6 months, there was a trend toward decreased repeated target-vessel interventions for atherectomy (P = .092); in addition, 13.2% of patients treated with atherectomy versus 22.4% of the angioplasty patients (P = .041) required repeated percutaneous intervention of the initial target lesion. CONCLUSIONS: Atherectomy of de novo vein graft lesions was associated with improved initial angiographic success and luminal diameter but also with increased distal embolization. There was no difference in 6-month restenosis rates, although primary atherectomy patients tended to require fewer target-vessel revascularization procedures.

Aged↗
PubMed1995

Transluminal extraction catheter for the treatment of diseased saphenous vein grafts: a multicenter experience.

To evaluate the efficacy, safety, and long-term results of atherectomy using the Transluminal Extraction catheter (TEC), patients with diseased saphenous vein grafts were enrolled in a prospective nonrandomized trial. Patients were followed to hospital discharge for acute complications and underwent routine 6-mo reevaluation with repeat cardiac catheterization to assess restenosis. Atherectomy was performed on 650 graft lesions in 538 consecutive patients (male 81%; mean age 66 yr; range 37-81). Mean graft age was 8.3 yr; (range 0.3-20) with 85% of grafts > 3 yr of age. Complex lesion morphology included thrombus (28%), ulceration (13%), and eccentricity (50%). Lesion success was achieved in 606 lesions (93%) with clinical success in 479 patients (89%). Lesion success was achieved in 90% of thrombus containing lesions, 97% of ulcerated lesions, and 97% of grafts > 3 yr. Complications included nonfatal myocardial infarction in 4 (0.7%) of patients, emergency bypass surgery in 2 (0.41%), and in-hospital death in 17 patients (3.2%). Angiographic follow-up at 6 mo was obtained from 268 lesions in 227 patients. The overall lesion angiographic restenosis rate was 60%. TEC atherectomy can be performed in patients with diseased saphenous vein grafts with high primary success and low complication rates. It is suitable for use in aged grafts, particularly in the presence of thrombus and ulcerations, and may be superior to balloon angioplasty alone in this group of patients.

Adult↗
PubMed1995

Early and 1-year survival rates in acute myocardial infarction complicated by cardiogenic shock: a retrospective study comparing coronary angioplasty with medical treatment.

Cardiogenic shock remains a frequently lethal complication of acute myocardial infarction. Early revascularization of the infarct-related artery by coronary angioplasty has been suggested to significantly improve patient survival. In-hospital and 1-year survival was assessed in 50 patients hospitalized for acute myocardial infarction complicated by cardiogenic shock. All patients received medical treatment and intraaortic balloon pump support. Thirty-three patients underwent coronary angioplasty (PTCA group), while 17 patients remained on conventional therapy (no PTCA group). The two groups were comparable for all baseline characteristics. Survival was significantly better in the PTCA group than in the no PTCA group: 64% versus 24% in-hospital survival (p = 0.007) and 52% versus 12% at 1 year (p = 0.006). When angioplasty was successful in achieving reperfusion, survival was further enhanced: in-hospital survival rate was 76% versus 25% in patients with unsuccessful angioplasty and 60% versus 25% at 1 year.

Aged↗