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Biomedical subjects

Jose A Silva

Publications and source records attributed to Jose A Silva.

10 recordsLinked to original sources
PubMed2007

Diabetes mellitus does not preclude stabilization or improvement of renal function after stent revascularization in patients with kidney insufficiency and renal artery stenosis.

OBJECTIVE: To assess the impact of stent revascularization on the renal function of diabetic and nondiabetic patients with renal insufficiency. BACKGROUND: Renal artery revascularization has been shown to stabilize or improve renal function in patients with significant renal artery stenosis and impaired renal function. However, some studies have suggested negligible or no benefit of renal function in diabetic patients with the same condition. METHODS: We retrospectively compared data from 50 consecutive patients undergoing renal artery stent placement with renal insufficiency (serum creatinine > or = 1.5-4.0 mg/dl) and global ischemia (bilateral or solitary [single] kidney renal artery stenosis) There were 17 diabetic (DM) and 33 nondiabetic (NDM) patients. The endpoints included the follow-up measurements of renal function, blood pressure, and number of antihypertensive medications. RESULTS: After stent placement, at a mean follow-up of 42 +/- 18 months (range: 6-62 months), 79% NDM (N = 26), and 76% DM patients (N = 13) (P = NS) had improvement in the slope of the reciprocal of creatinine (1/SCr), indicating a beneficial effect in renal function in many patients. CONCLUSION: Renal artery stent placement appears to be equally beneficial in preserving renal function in DM and NDM patients with ischemic nephropathy and global renal ischemia.

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PubMed2006

Endovascular therapy for chronic mesenteric ischemia.

OBJECTIVES: We sought to describe the outcomes of a consecutive series of patients with chronic mesenteric ischemia (CMI) who were treated with percutaneous stent revascularization. BACKGROUND: Historically, the treatment for CMI has been surgical revascularization. However, surgery carries a significant procedural complication rate and mortality. METHODS: Fifty-nine consecutive patients with CMI underwent stent placement in 79 stenotic (>70%) mesenteric arteries. All patients had clinical follow-up and 90% had anatomical follow-up with angiography (computed tomography or conventional) or ultrasound at > or =6 months after the procedure. RESULTS: Procedural success was obtained in 96% (76 of 79 arteries) and symptom relief occurred in 88% (50 patients). At a mean follow-up of 38 +/- 15 months (range, 6 to 112 months), 79% of the patients remained alive, and 17% (n = 10) experienced a recurrence of symptoms. Angiography or ultrasound obtained at 14+/- 5 months after the procedure demonstrated a restenosis rate of 29% (n = 20). All patients with recurrent symptoms had angiographic in-stent restenosis and were successfully revascularized percutaneously. CONCLUSIONS: Percutaneous stent placement for the treatment of CMI can be performed with a high procedural success and a low complication rate. The long-term freedom from symptoms and vascular patency are comparable with surgical results. The inherent lower procedural morbidity and mortality makes the endovascular approach the preferred revascularization technique for these patients.

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PubMed2005

Elevated brain natriuretic peptide predicts blood pressure response after stent revascularization in patients with renal artery stenosis.

BACKGROUND: A significant number (20% to 40%) of hypertensive patients with renal artery stenosis will not have blood pressure improvement after successful percutaneous revascularization. Identifying a group of patients with refractory hypertension and renal artery stenosis who are likely to respond to renal stent placement would be beneficial. METHODS AND RESULTS: Brain natriuretic peptide (BNP) was measured in 27 patients with refractory hypertension and significant renal artery stenosis before and after successful renal artery stent placement. This neuropeptide was elevated (median, 187 pg/mL; 25th to 75th percentiles, 89 to 306 pg/mL) before stent placement and fell within 24 hours of the successful stent procedure (96 pg/mL; 25th to 75th percentiles, 61 to 182 pg/mL; P=0.002), remaining low (85 pg/mL; 25th to 75th percentiles, 43 to 171 pg/mL) at follow-up. Clinical improvement in hypertension was observed in the patients with a baseline BNP >80 pg/mL (n=22) in 17 patients (77%) compared with 0% of the patients with a baseline BNP < or =80 pg/mL (n=5) (P=0.001). After correction for glomerular filtration rate, BNP was strongly correlated with improvement in hypertension. CONCLUSIONS: BNP is increased in patients with severe renal artery stenosis and decreases after successful stent revascularization. In addition, an elevated baseline BNP level of >80 pg/mL appears to be a good predictor of a blood pressure response after successful stent revascularization.

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PubMed2005

Endovascular treatment of a massive retroperitoneal bleeding: successful balloon-catheter delivery of intra-arterial thrombin.

Retroperitoneal bleeding is a potentially lethal complication of percutaneous intervention, when the common femoral artery is used as vascular access. Surgery, the traditional treatment for this complication in patients with persistent bleeding or hemodynamic instability, carries a considerable risk of morbidity and mortality. We report a case of life-threatening retroperitoneal bleeding successfully treated percutaneously with balloon occlusion and catheter delivery of thrombin to attain thrombosis of a lacerated branch of the common femoral artery. Endovascular catheter-based percutaneous treatment for massive retroperitoneal bleeding is often effective and should be pursued in selected patients.

Catheterization↗
PubMed2004

Percutaneous revascularization of the common femoral artery for limb ischemia.

We performed percutaneous transluminal intervention in 20 consecutive patients (21 limbs) with common femoral artery (CFA) lesions causing symptomatic limb ischemia. In 12 limbs, concurrent additional percutaneous intervention proximal or distal to the target CFA lesion was performed. Angiographic success was obtained in 100%, with procedural success (angiographic success without a major in-hospital complications) in 90% and clinical success (procedural success and in-hospital improvement by at least one Fontaine functional class) in 81% of the limbs. The in-hospital Fontaine class improved by at least one functional class in 17 of 19 patients (89%), and the overall in-hospital event-free survival was 90% (18 of 20 patients). At follow-up (11.4 +/- 6 months), the overall event-free survival was 90% (18 of 20 patients) and 17 of 19 patients (89%) continue to show improvement by at least one functional (Fontaine) class. Percutaneous intervention of the CFA can be performed with a rate of high technical success and a low complication rate. It provides excellent clinical results at mid-term follow-up and appears to be a reasonable alternative to surgical therapy in patients at high risk for surgery.

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PubMed2003

Treatment of coronary stent thrombosis with rheolytic thrombectomy: results from a multicenter experience.

The objective of this study was to assess the feasibility, efficacy, and safety of rheolytic thrombectomy (RT) for treatment of coronary stent thrombosis. Stent thrombosis is an infrequent but potentially devastating complication. Conventional treatment with balloon angioplasty and/or thrombolysis has yielded suboptimal results. RT was used to treat 18 patients (mean age, 62 +/- 8 years; 72% male) with in-stent thrombosis (mean time to stent thrombosis, 2.4 +/- 1.8 days). Device success, procedure success, in-hospital and 30-day major cardiovascular events (MACE) were assessed in the hospital and at 30 days. Device success was obtained in 94% and procedure success was achieved in 100% of patients. Following RT, 11 patients underwent balloon angioplasty and 7 patients received additional stents. TIMI 3 coronary flow was obtained in 94.4% and all (100%) patients achieved either TIMI 2 or 3 coronary flow. The angiographic thrombus area decreased from 113.7 +/- 79 to 5.5 +/- 5.7 mm(2) after RT, and to 0.9 +/- 2.1 mm(2) (P < 0.001) after final treatment. Procedural complications were limited to transient no-reflow in five patients. Only one patient evolved a Q-wave MI. At 30 days of follow-up, no patients suffered death, emergent bypass surgery, or stroke. Our data suggest that the adjunctive use of rheolytic thrombectomy offers improved outcomes compared to prior results of intervention after coronary stent thrombosis and should be strongly considered as a treatment option for this complication.

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PubMed2001

Percutaneous intervention of old degenerated saphenous vein grafts.

The treatment of failing bypass grafts is difficult because repeat surgery carries a higher mortality rate than a first operation. Percutaneous intervention is more difficult because mechanical manipulation of these soft, friable atherosclerotic plaques have been associated with a significant rate of distal embolization, myocardial infarction, late restenosis and death. Balloon angioplasty alone has proven to have serious limitations in the treatment of older degenerated saphenous vein grafts (SVG). Although directional atherectomy yielded a higher angiographic success in a randomized trial, the restenosis rate was similar, and the procedural complications higher. The transluminal extraction catheter (TEC) has also shown significant limitations for the treatment of degenerated or thrombotic vein grafts with a significant procedural complication rate. A randomized trial comparing stenting versus balloon angioplasty in focal SVG lesions showed a higher freedom from major adverse cardiovascular events in the stent group, but there was no significant difference in the angiographic restenosis rates. More recently, rheolytic thrombectomy and mechanical thrombolysis have proven useful in treating thrombotic lesions in SVG. In addition, the recent development of distal protection devices appears very promising and will probably contribute to decreased distal embolization during percutaneous revascularization of these conduits.

Journal Article↗
PubMed2001

Adjunctive pharmacologic treatment for elective stenting of the extracranial carotid arteries.

Endovascular stenting of the extracranial carotid arteries is a viable treatment option to carotid endarterectomy in selected patients. Patients undergoing this procedure must be treated with aspirin 325 mg at least 24 hours prior to the procedure and clopidogrel 75 mg oral, three to five days prior to the procedure (or 300 mg at least six hours prior to stenting). During the intervention, heparin is given to maintain an activated clotting time of at least 300 seconds. Although there are theoretical advantages on the use of a platelet IIb/IIIa inhibitor, their routine use during elective carotid stenting is not recommended until their clinical benefits have been clearly demonstrated in this patient population. Hemodynamic instability during balloon inflation and stent deployment should be treated with intravenous fluids, atropine, and an alpha agonist such as neosynephrine. All the oral antihypertensive must be discontinued after the procedure and if there is persistence of hypotension making discontinuation of neosynephrine difficult, an oral alpha agonist such as midodrine (2.5 to 5 mg two to three times daily) is helpful. In the majority of patients this medication can be tapered off three to five days following stenting.

Journal Article↗
PubMedDate not supplied

Plaque instability in peripheral vessels.

Vulnerable atherosclerotic plaques, those that are prone to rupture, are soft and lipid rich. Other factors that contribute to destabilizing these plaques are inflammation and vasoconstriction. Although less information is available regarding noncoronary vulnerable plaques than the more frequently studied coronary plaques, it appears that the amount of soft lipid "gruel" as well as in situ inflammation plays a crucial role in destabilizing peripheral vascular atherosclerotic plaque, eventually causing its rupture. As in the coronary circulation, it is likely that the majority of acute plaque rupture events are clinically silent. Nevertheless, preventing plaque rupture in the noncoronary circulation is of the utmost importance because this is the presumed mechanism of progression of peripheral vascular atherosclerotic lesions.

Arteriosclerosis↗