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Biomedical subjects

R F Lewin

Publications and source records attributed to R F Lewin.

At least 19 recordsLinked to original sources
PubMed1992

Milwaukee Prehospital Chest Pain Project--phase I: feasibility and accuracy of prehospital thrombolytic candidate selection.

This study prospectively determined the feasibility and accuracy of prehospital thrombolytic therapy candidate selection by base station emergency physicians. During a 6-month period, paramedics acquired and transmitted prehospital 12-lead electrocardiograms (ECGs) and then applied a thrombolytic therapy contraindication checklist. Emergency physicians interpreted prehospital ECGs and prospectively selected candidates for thrombolytic therapy. A safety committee of cardiologists reviewed prehospital ECGs, checklists and hospital records to determine accuracy independently. Six hundred-eighty stable adult prehospital patients with a chief complaint of nontraumatic chest pain were initially evaluated. Two hundred forty-one patients were excluded because of (1) unsuccessful electrocardiographic transmission (149), (2) transport to nonparticipating facilities (72), and (3) unavailable medical records (20). No prehospital thrombolytic therapy was administered in this study. Of 439 cases, 91 (21%) had the final diagnosis of acute myocardial infarction, 38 (8.7%) had diagnostic prehospital ECGs, and 12 (2.7%) were selected by emergency physicians as candidates for thrombolytic therapy. Seventy percent of patients with myocardial infarction had checklist exclusions for thrombolytic therapy. Prehospital evaluation increased mean scene time (paramedic arrival on scene to scene departure) by 4 minutes. The median time from chest pain onset to paramedic arrival in patients with myocardial infarction was 60 minutes. The estimated average time saved if prehospital thrombolytic therapy had been available was 101 +/- 81 minutes. The safety committee concluded that acceptable accuracy of emergency physician prehospital electrocardiographic interpretation, checklist and case selection was achieved. It is concluded that emergency physicians can accurately identify candidates for prehospital thrombolytic therapy.

Adult↗
PubMed1991

Catheter balloon valvuloplasty of stenotic aortic valves--Part II: Balloon valvuloplasty during life subsequent tissue examination.

This review describes 23 patients with aortic valve stenosis who underwent balloon valvuloplasty during life and had subsequent valve tissue examined at the time of aortic valve replacement or at necropsy. Of 23 stenotic aortic valves, 17 were examined within 30 days (early) after balloon dilation. Of these 94% had nonrheumatic (nonfused commissures) etiologies for the aortic stenosis. Of the 6 valves examined after 30 days (late) (restenosis), mechanisms of restenosis involve refusion of split commissures and probable elastic recoil. Clinical prediction of the aortic stenosis etiology prior to balloon valvuloplasty may help predict short- and long-term success of the dilation procedure.

Adult↗
PubMed1990

Peripheral transluminal angioplasty of the subclavian and innominate arteries utilizing the brachial approach: acute outcome and follow-up.

Percutaneous transluminal angioplasty (PTA) of the subclavian and innominate arteries was performed in 27 patients at 33 sites (30 subclavian, 3 innominate). All procedures were successful angiographically and clinically and were without complication. The ipsilateral arm was utilized in all cases. Indications for the procedure included claudication (ten patients), neurological symptoms (seven patients), to gain vascular access for other interventions (eight patients), and scheduled coronary bypass surgery with internal mammary utilization (two patients). There were 22 stenoses and 11 occlusions. Thrombi was retrogradely recovered through the arteriotomy site in three patients with vessel occlusions. No early or late episode of neurological deficit was seen. Follow-up was obtained in 22 patients (82%) at a mean time of 28 months (range, 2-73 months). The cumulative patency rate was 95%. The three restenosed sites were treated with successful repeat PTA. Angioplasty of stenotic or occluded subclavian or innominate arteries should be the procedure of choice in symptomatic patients.

Adult↗
PubMed1990

Below-the-knee angioplasty: tibioperoneal vessels, the acute outcome.

Conventional balloon angioplasty (PTA) was attempted in 111 patients (60% male; mean age 67 +/- 9 years) with 168 below-the-knee, tibioperoneal vessels (TPV) lesions. The presenting predominant symptoms were claudication in 52 (47%), non-healing ulcer/gangrene in 30 (27%), and rest pain in 29 (26%) of patients. An above-the-knee vessel was dilated before TPV angioplasty in 62 patients (56%). A successful PTA was achieved in 152/168 (90%) TPV: stenoses, 124/125 (99%); occlusions, 28/43 (65%). Complications encountered included contrast-induced renal failure (4%), distal embolization (4%), entry site arterial repair or embolectomy (2%), dissection or occlusion (2%), and groin hematoma (2%). A significant complication (death, emergency bypass surgery, or distal embolization) occurred in only 3 patients (3%); no complications whatsoever were found in 100 patients (90%). At discharge, 106 patients (95%) were clinically improved. A restenosis and/or second PTA procedure occurred in 44/108 patients (40%) (mean time: 9 +/- 6 months) with the presenting predominant symptom being claudication in 38 patients (86%). However, only 36% of patients had lesion recurrence with or without new disease, and 64% showed evidence of disease progression with symptoms. Angiographic and clinical success was achieved in 42 patients undergoing second PTA (96%). These data indicate that balloon angioplasty can be successfully utilized in patients with symptomatic obliterative disease of the tibioperoneal vessels with excellent success, a low risk of complications, and good clinical improvement. PTA of the below-knee vessels should not be restricted to patients in limb salvage situations.

Aged↗
PubMed1990

Retrograde recanalization of an occluded posterior tibial artery by using a posterior tibial cutdown: two case reports.

Recanalization of two occluded posterior tibial arteries was successfully achieved by utilizing a retrograde approach via a posterior tibial artery cutdown at the level of the ankle. Both cases were previously unsuccessfully attempted by using an antegrade approach. Thus, the choice of access vessel (arterial entry site) becomes a crucial determinant of angioplasty success.

Angiography↗
PubMed1990

Percutaneous popliteal approach for angioplasty of superficial femoral artery occlusions.

Angioplasty using the percutaneous popliteal approach was utilized in 50 patients (PTS) to recanalize 59 occluded superficial femoral arteries which had been unsuccessfully canalized by using the antegrade approach because of either a flush origin occlusion or inability to maintain the guide wire in the true lumen. All PTS had claudication; 8 had rest pain; 3 had non-healing ulcers. The laser Probe was used in 17 cases and the Rotablator in 3 cases. Occlusion length varied between 1 and 40 cm: 7 lesions were less than 10 cm (group 1); 9 were between 10 and 20 cm (group 2); and 43 were greater than 20 cm (group 3). An angiographic success was obtained in 48/59 lesions (81%): 14/16 (87%) in groups 1 and 2 and 34/43 (79%) in group 3. Three PTS needed complementary common femoral endarterectomy and one required percutaneous aspiration of a thromboembolus. Complications included: arterial perforation and/or dissection (without clinical sequelae) in 11 and a popliteal hematoma in 1 PT. One patient with a severely ischemic leg underwent successful emergency vascular surgery, while another limb salvage patient required below-knee amputation. There was no worsening of limb ischemia from any popliteal approach attempt. At discharge, 39 patients (78%) whose outcome would have been unsuccessful with the traditional antegrade approach were clinically improved after utilizing the popliteal approach to achieve a successful angioplasty procedure.

Aged↗
PubMed1990

Percutaneous transluminal angioplasty in patients greater than or equal to 5 years after their last coronary bypass graft surgery.

Angioplasty (PTCA) was successfully performed in 257 of 304 patients (85%) greater than or equal to 5 years after their last bypass surgery. A lesion was successfully dilated in 496 of 566 vessels attempted (88%): 332/386 coronary arteries (86%) and 164/180 vein grafts (91%). Significant complications included: 8 (2.6%) mortalities, 4 (1.3%) emergency surgeries, 13 (4.3%) Q-wave myocardial infarctions, and 14 (4.6%) distal embolizations. Distal embolization occurred in 13/180 (7%) vein graft lesions dilated and usually resulted in a non-Q-wave infarction (4/13 distal embolizations). A second PTCA was performed on 89 (35%) patients: 44% of them had lesion recurrence; 20% a new lesion requiring dilatation; and 30% both recurrence and new lesion. Follow-up (mean 3.7 years) revealed 78% of patients having an improved anginal status, and 58% no angina. The cumulative probability of survival at 60 months was 88 +/- 3%. Angioplasty can be effectively employed in patients greater than or equal to 5 years remote from their last bypass surgery in native arteries or saphenous vein grafts with good procedural and long-term success. Vein graft age inherently does not appear to be a contraindication to angioplasty.

Aged↗
PubMed1990

Stimulation of atrial natriuretic peptide and vasopressin during retrograde mitral valvuloplasty.

Acute mitral obstruction may lead to an increase in atrial natriuretic peptide (ANP) due to increased atrial pressure and a large increase in arginine vasopressin (AVP) due to simultaneous arterial and ventricular baroreceptor unloading. We measured ANP and AVP concentration after transseptal puncture and during percutaneous retrograde mitral balloon valvuloplasty (PRMV) in 11 patients (mean age 57 +/- 12 years; nine women) with mitral stenosis and congestive heart failure. Atrial septal puncture per se resulted in a significant increase in ANP and AVP without a significant change in aortic pressure. Subsequent PRMV led to a further increase in ANP, a transient decrease in aortic pressure from 89 +/- 7 to 45 +/- 4 mm Hg, and a large (fivefold) increase in AVP. ANP and AVP were no longer different from baseline values 18 to 24 after the procedure. This study suggests that transseptal puncture and acute mitral obstruction are major stimuli to ANP release and that combined unloading of arterial and left ventricular mechanoreceptors is a very potent vasopressinergic stimulus.

Aged↗
PubMed1990

Percutaneous transluminal aortic valvuloplasty--the acute outcome and follow-up of 149 patients who underwent the double balloon technique.

Double balloon percutaneous transluminal aortic valvuloplasty (PTAV) was performed on 149 patients (76 male (51%), mean age 76 +/- 11 years) whose symptoms included severe congestive heart failure in 127 cases (82%), syncope in 21 (14%) and angina in six (4%). Significant changes (P less than 0.05) in peak systolic (83 +/- 36 to 38 +/- 30 mmHg) and mean gradient (68 +/- 25 to 36 +/- 21 mmHg), and aortic valve area (0.6 +/- 0.2 to 1.0 +/- 0.4 cm2) were achieved in 130/149 patients (87%). Complications included an overall in-hospital mortality of 13%, (10.0% excluding the six deaths occurring in 18 moribund patients), a neurologic deficit incidence of 3%, and surgical arterial entry site repair 3.0% (14/47) of patients. Multivariate analysis identified congestive heart failure (NYHA Class IV), left ventricular ejection fraction, cardiac output and coronary artery disease as independent variables significantly affecting in-hospital mortality. Predictors of poor long-term survival were degree of heart failure, and coronary artery disease. The cumulative probability of survival at 24 months was 52 +/- 5% (excluding non-cardiac deaths, was 66 +/- 3%). Follow-up (mean time: 16 +/- 7 months) of 130 patients discharged alive revealed 41 late deaths (26 cardiac related). Sixty-two patients (70%) were symptomatically improved; 17 patients had symptom recurrence and underwent repeat valvuloplasty, and 10 patients valve replacement. Follow-up catheterization of 18 asymptomatic patients revealed that 11 patients had silently restenosed. These data indicate that aortic valvuloplasty is a palliative therapy for elderly patients, who are poor surgical candidates, with symptomatic calcific aortic stenosis with reasonable clinical success and long-term survival when considering their clinical status, but with a significant restenosis rate.

Aged↗
PubMed1989

Percutaneous transluminal aortic valvuloplasty: acute outcome and follow-up of 125 patients.

Percutaneous transluminal aortic valvuloplasty was performed on 125 patients (59 men [47%], mean age 76 +/- 13 years) between July 1986 and May 1988, with presenting symptoms of severe congestive heart failure in 88 (70%), moribund state in 15 (12%) and syncope in 17 (14%). Surgical valve replacement was considered unsuitable in 79% of cases. A multiple balloon technique was utilized in 119 patients (95%). Valvuloplasty produced significant changes in peak pressure gradient (87 +/- 38 to 32 +/- 17 mm Hg), mean pressure gradient (70 +/- 26 to 30 +/- 13 mm Hg) and valve area (0.6 +/- 0.2 to 1.0 +/- 0.3 cm2). Complications included: in-hospital mortality in 10% (6 of 13 deaths in moribund patients), neurologic deficit in 3% and myocardial infarction in 2%. Arterial repair was required at 12 (4%) of 325 entry sites. Multivariate analysis identified severe congestive heart failure, preprocedure left ventricular ejection fraction and cardiac output as the only independent variables significantly affecting mortality. The cumulative probability of survival at 12 months was 62 +/- 6% and, excluding non-cardiac deaths, was 77 +/- 5%. At a mean of 12 +/- 4 months' follow-up, 55 of 72 patients were symptomatically improved; 10 patients with symptom recurrence underwent repeat valvuloplasty and 5 had valve replacement. Cardiac catheterization was repeated in 12 symptomatically improved patients, 9 of whom had valve restenosis. These data indicate that aortic valvuloplasty should be considered a palliative therapy for elderly patients with symptomatic calcific aortic stenosis who are poor surgical candidates.

Aged↗
PubMed1989

Aortic annular tear after valvuloplasty: the role of aortic annulus echocardiographic measurement.

Following percutaneous transluminal aortic valvuloplasty, 2/100 patients (2%) developed significant aortic insufficiency as a result of an aortic annular tear. Both patients underwent emergency aortic valve replacement and survived the operation. One patient died 4 weeks postoperatively from sepsis and multiorgan failure, and the other patient had a benign postoperative course. In both cases, the balloon area significantly exceeded the aortic annular area and caused the complication. Review of the balloon area-aortic annular area ratio in our series showed that a value of less than 1.2 was not associated with this complication.

Aged↗
PubMed1989

The Probe exchange catheter.

In order to provide exchange capability to non-over-the-wire systems (i.e., Probe), an exchange catheter composed of an inner sheath catheter (.039'' external diameter) and a 4 French outer catheter was devised. The system was utilized to exchange between an over- to a non-over-the-wire system, different non-over-the-wire systems, and to provide balloon dilatation backup to the soft non-over-the-wire systems in difficult-to-engage vein graft takeoff. The system was successfully utilized in 50 patients without any related complications.

Aged↗
PubMed1989

Percutaneous aspiration of a thromboembolus.

Percutaneous aspiration of a thromboembolus was successfully performed in 12 out of 13 patients with in situ thrombosis (4 patients), distal embolization (7 patients), or both (2 patients). The flow was improved from TIMI 0 (10 patients, no flow) or TIMI 1 (2 patients, impaired flow) to TIMI 3 (10 patients, normal flow) or TIMI 2 (2 patients, normal but slower flow). A custom-made 8 F Teflon-coated sheath was introduced in the superficial femoral and proximal below-the-knee arteries to aspirate the debris. Distal embolization in below-the-knee arteries was concomitantly treated with short-term intraarterial Urokinase in nine patients. Complications included one in-hospital (not procedure related) death, two patients with below-the-knee amputations (above-the-knee amputation averted), and one transmetatarsal amputation (prior established gangrene present and below-the-knee amputation avoided). The remaining nine patients left the hospital with improved limb status and peripheral pulses. This technique is a rapid, reliable, and efficient method to treat in-situ clot or procedure-related distal embolization as an adjuvant or complement to lytic treatment.

Aged↗
PubMed1989

Percutaneous atherectomy of occlusive peripheral vascular disease: stenoses and/or occlusions.

Percutaneous atherectomy was performed using the Simpson Atherocath on 131 patients (87 male, 66%) with a mean age of 65 years. Clinical characteristics included evidence of significant coronary disease in 50%, hypertension in 46%, diabetes in 41%, and prior neurologic deficit in 32% of patients. The indication for atherectomy was claudication in 114 (87%) and rest pain, gangrene, or ulcer in 17 patients (13%). Atherectomy was successfully performed in 136/139 stenoses (98%) and in 56/56 occluded vessels with or without prior balloon angioplasty. No serious complications resulting in limb loss or emergency vascular surgery were encountered. Histopathology of retrieved specimens showed that 66% had atheromatous plaque, 45% had tunica media, and 30% had a form of thrombus. Material obtained from an occluded vessel was more likely to have thrombus and tunica media present than that from a stenosis (P less than 0.02 and P less than 0.05, respectively). Early angiographic follow-up (mean time, 17 weeks) showed a relatively low (17%) lesion recurrence rate. Percutaneous atherectomy can be successfully utilized in stenotic and occluded peripheral arteries with good success and no serious complications; stenoses appear to have a low recurrence rate.

Aged↗
PubMed1989

Stimulation of atrial natriuretic peptide and vasopressin during percutaneous transluminal aortic valvuloplasty.

The objective of this study was to determine the effects of transient aortic valve occlusion (balloon valvuloplasty) on vasoactive hormones in patients with heart failure. Plasma atrial natriuretic peptide, vasopressin, aldosterone, adrenocorticotropic hormone (ACTH), and plasma renin activity were measured before, immediately after, and 30 minutes and 18 to 24 hours following balloon inflation in 18 patients. Mean right atrial and pulmonary wedge pressures were 6 and 18 mm Hg before inflations, respectively, and were unchanged after balloon inflations (5 and 13 mm Hg, respectively). Systemic systolic/diastolic pressures were 139 +/- 8/65 +/- 4 mm Hg before occlusion, decreased to 47 +/- 5/34 +/- 3 mm Hg during occlusion, and returned to baseline after occlusions. Baseline atrial natriuretic peptide levels were 267 +/- 43 pg/ml and increased to 513 +/- 71 pg/ml after balloon inflations. Vasopressin levels before occlusion were 9.1 +/- 2.2 pg/ml and increased to 21.4 +/- 4.8 pg/ml after balloon inflations. Plasma renin activity was 5.4 +/- 1.4 ng/ml/hr before inflations and was not significantly changed after balloon inflations. No clinically significant changes in plasma sodium, potassium, creatinine, and osmolality were observed after the procedure. Aldosterone increased from 23 +/- 4 to 40 +/- 7 ng/dl 10 minutes after the last inflation. Plasma ACTH measured in seven patients with increased aldosterone was 28 +/- 8 pg/ml before and increased to 295 +/- 157 pg/ml 10 minutes after balloon inflations. The increases in natriuretic peptide and vasopressin were likely due to elevated intracardiac and decreased arterial pressures, respectively; they persisted in spite of no clinically significant changes in filling pressures 12 to 24 hours after the procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1989

[Complex angioplasty. (I). Single dilatation versus multiple dilatation in patients with multi-vessel coronary disease].

Coronary angioplasty was successfully performed in 658/752 multivessel disease patients. One lesion was attempted in 338 patients (45%); two or more in 414 patients (55%). Complications occurred in 39 patients (5.2%): 19 (2.5%) had a transmural infarction, 26 (3.5%) urgent surgery, and 14 (1.9%) died. Recurrence occurred in 233/658 (35%) patients with 162/171 (94.7%) having a successful second angioplasty. Clinical improvement (follow-up: 31 months) remained in 81% of successful patients. Survival was not affected by the number of dilations performed but was adversely affected by the presence of prior surgery and ventricular dysfunction. Angioplasty can be an effective treatment without the need to dilate all vessels.

Aged↗
PubMed1989

[Complex coronary angioplasty (II). Dilatation of multiple lesions in single-vessel and multi-vessel coronary disease].

Angioplasty (PTCA) was successfully performed in 404/428 patients (94%). Two lesions were attempted in 74%; three in 21%; and four or more in 6% of cases. Significant complications included: 11 (2.5%) transmural infarctions, 9 (2.1%) emergency surgeries, and 6 (1.4%) mortalities. A lesion recurrence occurred in 106/404 patients (26%) with 81/89 patients (91%) having a successful second PTCA. A second recurrence occurred in 15/81 patients (19%) with 13/15 patients having a successful third PTCA. Follow-up (mean: 28.3 months) showed an improved anginal status in 83% of patients. The probability of survival at 51 months was 93%. Multiple lesion PTCA in carefully selected patients has a good success rate, an acceptable complication rate, and a reasonable expectation of satisfactory long-term results, with or without the need for subsequent PTCA procedures.

Angioplasty, Balloon↗