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Biomedical subjects

M Razavi

Publications and source records attributed to M Razavi.

43 records · Page 3Linked to original sources
PubMedDate not supplied

Response of balloon-expandable endoprosthetic metallic stents subjected to over-expansion in vitro.

We attempted to evaluate the in vitro behavior and performance of balloon-expandable endoprosthetic metallic stents subjected to over-expansion (OE). Seventy-two balloon-expandable endoprosthetic stents, representing 22 models from six manufacturers, were overexpanded in vitro. Stents were initially expanded to their maximum manufacturer- recommended diameter and then over-expanded incrementally to their endpoints. Endpoints for OE were either stent disarticulation or an inability to undergo further expansion despite balloon insufflation to maximum burst pressure. Measurements of stent dimensions were recorded at each overexpanded diameter and comparisons were made to manufacturer's specifications. A total of 288 balloon-driven expansions were performed on 72 stents. Sixteen stents were expanded to large diameters (> or = 16 mm), 20 stents underwent OE of 50% or greater. One model tended to disarticulate after OE greater than 50%. There were five models that had a tendency to disarticulate after minimal OE. Five models were resistant to OE (25% or less OE) but did not disarticulate. Nearly all stents showed some degree of foreshortening with OE, while 36 stents underwent foreshortening of 30% or more. Models that are not recommended for OE include Intrastent, Intrastent DoubleStrut, NIR Royale and Omniflex. Good candidates for OE include Intrastent DoubleStrut LD, Palmaz large, Medtronic Extra Support Biliary Plus and Medtronic Flexible Biliary. Palmaz XL remains the only model available for expansion from 20 to 28 mm in diameter. For the remaining stents, OE is possible, however, caution should be used.

Catheterization↗
PubMedDate not supplied

Surgical treatment of coronary artery disease: pure graft operations, with a study of 741 patients followed 3--7 yr.

This report reviews the experience with bypass graft surgery in the pure form, without associated cardiac procedures, in 6828 patients operated upon from 1967 through 1974. The hospital mortality rate in this group was 1.4%. The incidence of definite perioperative myocardial infarction was 6.9% prior to 1971, and 4.1% in the past 3 yr. Graft patency in postoperative studies performed an average of over 12 mo after surgery was 83.6%, and 89% of patients had one or more functioning grafts. In a subgroup of 741 consecutive patients operated upon with pure graft techniques from 1967 through 1970, survival seemed to be improved when compared to another group of similar, but nonoperated patients. The average annual mortality rate was 3.3% per yr in the surgical group (including surgical mortality) compared to 8.8% per year in the medical group. Differences in survival were most striking in patients with isolated anterior descending, double and triple vessel involvement. In the 741-patient subgroup the incidence of new occlusions of grafted arteries was related to the severity of the lesion(s) for which the operation was performed, and unrelated to graft patency. Arteriographically demonstrated new occlusions of ungrafted arteries were infrequent, and few patients developed significant new lesions during the period of observation. Symptomatic improvement is related to completeness of revascularization as determined by postoperative arteriography.

Angiocardiography↗
PubMedDate not supplied

Transbronchial Palmaz stent placement for tracheo-bronchial stenosis.

PURPOSE: Evaluation of the efficacy of transbronchial Palmaz stent placement in the treatment of tracheo-bronchial narrowing. MATERIALS AND METHODS: Twelve patients with stenoses of the tracheo-bronchial tree were treated with balloon-expandable Palmaz stents. Etiology was anastomotic stenosis after lung transplantation (n = 3), bronchogenic carcinoma (n = 2), external compression from thoracic aortic aneurysm (n = 2), Mycobacterium tuberculosis (n = 1), esophageal carcinoma (n = 1), after lobectomy (n = 1), after lobectomy and endobronchial radiation (n = 1), and lye ingestion (n = 1). All patients had respiratory symptoms, radiologic findings of persistent atelectasis, or worsening pulmonary function tests. Bronchoscopy was used to delineate the stenosis prior to intervention. With use of fluoroscopic guidance, stents were placed in the mainstem bronchus (n = 11), lower lobe bronchus (n = 5), bronchus intermedius (n = 5), trachea (n = 3), and middle lobe bronchus (n = 1). RESULTS: Initial technical success was achieved in all patients. Ten of the 12 patients (83%) had improvement of clinical pulmonary signs or symptoms. During follow-up, five patients died. One was lost to follow-up and was presumed dead. The 30-day mortality rate was 17% (two of 12 patients). The two complications were superficial laceration of the bronchial mucosa during balloon dilation in one patient and compression of stents by a thoracic aortic aneurysm in another patient. CONCLUSION: Initial results suggest that transbronchial Palmaz stent placement is a feasible and effective method of treating tracheo-bronchial stenosis.

Adult↗
PubMedDate not supplied

Right heart failure after chemotherapy.

Cardiotoxicity associated with chemotherapeutic agents used in the treatment of cancer is well-documented. Usually this cardiotoxicity presents as a distinct syndrome in which the left ventricle is more seriously affected than the right ventricle. A case of severe right-sided ventricular dysfunction shortly after an aggressive cycle of chemotherapy for metastatic colon carcinoma is presented.

Antineoplastic Agents↗
PubMedDate not supplied

Acute dissection of the aorta: options for diagnostic imaging.

When dissection of the aorta is suspected, the physician needs to initiate medical therapy immediately, even before a final diagnosis is made. New imaging technologies are essential in making a diagnosis. In some cases, these new imaging modalities obviate the need for angiography.

Aortic Dissection↗