Dinesh Shaw

Renal Artery Stent Placement: Utility in Lesions Difficult to Treat With Balloon Angioplasty

OBJECTIVES We assessed the safety and efficacy of stent placement in patients with poorly controlled hypertension and renal artery stenoses, which are difficult to treat with balloon angioplasty alone. BACKGROUND Preliminary experience with stent placement suggests improved results over balloon angioplasty alone in patients with atherosclerotic renal artery stenosis. METHODS Balloon-expandable stents were placed in 100 consecutive patients (133 renal arteries) with hypertension and renal artery stenosis. Sixty-seven of the patients had unilateral renal artery stenosis treated and 33 had bilateral renal artery stenoses treated with stents placed in both renal arteries. RESULTS Angiographic success, as determined by quantitative angiography, was obtained in 132 (99%) of 133 lesions. Early clinical success was achieved in 76% of the patients. Six months after stent placement, the systolic blood pressure was reduced from 173 +/- 25 to 147 +/- 23 mm Hg (p < 0.001); the diastolic pressure from 88 +/- 17 to 76 +/- 12 mm Hg (p < 0.001); and the mean number of antihypertensive medications per patient from 2.6 +/- 1 to 2.0 +/- 0.9 (p < 0.001). Angiographic follow-up at a mean of 8.7 +/- 5.0 months in 67 patients revealed restenosis (>50% diameter narrowing) in 15 (19%) of 80 stented vessels. CONCLUSIONS Renal artery stenting is an effective treatment for renovascular hypertension, with a low angiographic restenosis rate. Stent placement appears to be a very attractive therapy in patients with lesions difficult to treat with balloon angioplasty such as renal aorto-ostial lesions and restenotic lesions, as well as after a suboptimal balloon angioplasty result.

Coronary Thrombi Increase PTCA Risk Angioscopy as a Clinical Tool

BACKGROUND The presence of angiographically identified intracoronary thrombus has been variably associated with complications after coronary angioplasty. Angiography has been shown to be less sensitive than angioscopy for detecting subtle details of intracoronary morphology, such as intracoronary thrombi. The clinical importance of thrombi detectable by angioscopy but not by angiography is not known. METHODS AND RESULTS Percutaneous coronary angioscopy was performed in 122 patients undergoing conventional coronary balloon angioplasty (PTCA) at six medical centers. Unstable angina was present in 95 patients (78%) and stable angina in 27 (22%). Therapy was not guided by angioscopic findings, and no patient received thrombolytic therapy as an adjunct to angioplasty. Coronary thrombi were identified in 74 target lesions (61%) by angioscopy versus only 24 (20%) by angiography. A major in-hospital complication (death, myocardial infarction, or emergency bypass surgery) occurred in 10 of 74 patients (14%) with angioscopic intracoronary thrombus, compared with only 1 of 48 patients (2%) without thrombi (P = .03). In-hospital recurrent ischemia (recurrent angina, repeat PTCA, or abrupt occlusion) occurred in 19 of 74 patients (26%) with angioscopic intracoronary thrombi versus only 5 of 48 (10%) without thrombi (P = .03). Relative risk analysis demonstrated that angioscopic thrombus was strongly associated with adverse outcomes (either a major complication or a recurrent ischemic event) after PTCA (relative risk, 3.11; 95% CI, 1.28 to 7.60; P = .01) and that angiographic thrombi were not associated with these complications (relative risk, 0.85; 95% CI, 0.36 to 2.00; P = .91). CONCLUSIONS The presence of intracoronary thrombus associated with coronary stenoses is significantly underestimated by angiography. Angioscopic intracoronary thrombi, the majority of which were not detected by angiography, are associated with an increased incidence of adverse outcomes after coronary angioplasty.

Effects of Renal Artery Stent Implantation in Patients With Renovascular Hypertension Presenting With Unstable Angina or Congestive Heart Failure

This study evaluates the effect of renal artery stent implantation in patients with renovascular hypertension presenting with unstable angina (n = 20) or congestive heart failure (n = 28). There was a significant improvement in the Canadian Cardiovascular Society angina class and the New York Heart Association functional class, and at 8.4 +/- 6.4 month follow-up.

Comparison of Surgical Bypass and Percutaneous Balloon Dilatation With Primary Stent Placement in the Treatment of Central Venous Obstruction in the Dialysis Patient: One-Year Follow-up

Central venous stenosis and occlusion are complications that are being observed with increasing frequency as a result of the use of long-term central venous catheters. These complications are especially problematic in patients with end-stage renal disease and functioning ipsilateral arteriovenous (AV) grafts or fistulas (AV grafts). We have previously demonstrated that the 1-year patency rate for simple balloon angioplasty in these patients is less than 10%. To compare the results of surgical treatment vs. percutaneous dilatation with stent placement, we undertook this retrospective study. All patients underwent multiple central venous catheter placements and had functioning ipsilateral AV grafts. Twenty-six patients were divided into two groups. The surgical treatment group included 13 patients: 10 with subclavian vein thrombosis and three with innominate vein thrombosis. All patients in the surgical group had arm swelling and edema. Surgical bypass procedures were performed in these patients using either polytetrafluoroethylene or saphenous vein. The stent group also included 13 patients; all of them had a diagnosis of subclavian or innominate vein obstruction and were treated with percutaneous transluminal angioplasty and placement of either a self-expanding rigid stent (n=6) or a balloon-expandable flexible stent (n=7). Two patients required multiple stent placements. No significant complications occurred in either group. The 1-year mortality rate in both groups was 31%. The percentages of patients who were symptom free at 6 and 12 months were also similar in the two groups. We conclude that surgical bypass and percutaneous transluminal angioplasty with stent placement are both efficacious in the treatment of central venous obstruction.

Two-Year Results of Paclitaxel-Eluting Stents in Patients With Medically Treated Diabetes Mellitus from the TAXUS ARRIVE Program

Drug-eluting stents decrease revascularization compared with bare metal stents in diabetic patients, but few studies have compared drug-eluting stent use in diabetic versus nondiabetic patients. The objective of this study was to assess whether paclitaxel provides equivalent revascularization decrease in diabetic and nondiabetic patients. The ARRIVE registries enrolled 7,492 patients receiving TAXUS Express stents, including 2,112 with medically treated diabetes; results were compared with those in the remaining 5,380 nondiabetic patients. Two-year target lesion revascularization (TLR) was comparable in diabetic and nondiabetic patients (8.2% vs 7.7%, p = 0.59) and remained similar after multivariate adjustment for baseline differences (7.1% vs 6.8%, p = 0.41). There were no significant TLR differences between diabetic and nondiabetic patients with small vessels (9.7% vs 9.5%, p = 0.96) or left main coronary artery, 3-vessel, or bifurcation stenting (10.7% vs 13.1%, p = 0.41). Diabetes was not a significant TLR predictor (hazard ratio 0.92, 95% confidence interval 0.77 to 1.12, p = 0.41). Stent thrombosis (2.6% vs 2.4%, p = 0.55) and myocardial infarction (3.8% vs 3.0%, p = 0.09) rates were also similar for diabetic and nondiabetic patients. However, 2-year mortality was significantly increased in diabetic compared with nondiabetic patients (9.7% vs 5.3%, p <0.001). Increased mortality drove significantly increased major cardiac events in diabetics; however, there was no difference in stent-related major cardiac events (8.9% vs 10.1%, p = 0.13). In conclusion, these results suggest that TAXUS paclitaxel-eluting stents abrogate the increased diabetic risk of clinical restenosis previously reported with bare metal stents, with similar low risk of myocardial infarction or stent thrombosis for diabetic and nondiabetic patients. However, diabetic patients still have increased risk of 2-year mortality.

Effect of gender on outcomes following renal artery stent placement for renovascular hypertension

To study the effect of gender on outcome following renal artery stent placement for renovascular hypertension, we prospectIvely followed 66 patients (30 males, 36 females) who underwent Palmaz stent placement in 89 renal arteries. There was no difference in the incidence of procedure-related complications between males and females. At 6-mo follow-up, the decrease in systolic (35 +/- 30 mm Hg and 27 +/- 25 mm Hg) and diastolic (15 +/- 23 mm Hg and 14 +/- 14 mm Hg) blood pressures was similar in female and male patients, respectIvely. Late follow-up at 19 +/- 11 mo also showed no difference in blood pressure response. In 44 patients who underwent repeat angiography at a mean duration of 9.1 +/- 5.6 mo after stent deployment, the incidence of restenosis was 26% in females and 24% in males (P = 0.85). We conclude that gender has no effect on the incidence of complications, blood pressure response, or angiographic restenosis in patients undergoing renal artery stent placement.

Endovascular stenting for treatment of an adult patient with pulmonary artery stenosis with 1-year follow-up

This report describes the occurrence of symptomatic proximal left main pulmonary artery stenosis in a 58-yr-old man that was successfully treated with endovascular stenting with 1-yr follow-up. The technique and pitfalls of this procedure are described. Endovascular stenting provided a well-tolerated, nonsurgical approach to alleviating isolated pulmonary artery stenosis in this patient.