PubMed Health⌕ Search

Biomedical subjects

John R Laird

Publications and source records attributed to John R Laird.

17 recordsLinked to original sources
PubMed2006

Perforation complicating carotid artery stenting: the use of a covered stent.

Carotid artery angioplasty and stenting has emerged as an effective strategy for the treatment of significant carotid artery stenosis. Perforation during carotid artery stenting is a very rare potential complication of the procedure. We describe a case of carotid artery perforation that occurred during postdilation of the carotid artery stent. In our case this potentially serious complication was successfully treated with a covered stent-graft.

Aged↗
PubMed2006

Limitations of percutaneous transluminal angioplasty and stenting for the treatment of disease of the superficial femoral and popliteal arteries.

The long-term primary patency rates for percutaneous transluminal angioplasty (PTA) and stenting in treatment of disease of the superficial femoral and popliteal arteries have been disappointing. Three-year primary patency rates of approximately 50% have been reported for PTA and first-generation stents. Early results with newer nitinol stents appear promising; however, long-term data are lacking. One- and 2-year primary patency rates of 76% to 97% and 60% to 84%, respectively, have been reported with nitinol stents. An emerging concern with nitinol stents is the frequency of stent fracture (> or = 25%) after interventions for long-segment disease. A recent study has shown that stent fractures are associated with in-stent restenosis and with significantly lower primary patency at 1 year. The therapeutic success of PTA and stenting correlates with the complexity of the underlying disease. The best results are achieved when treating focal stenoses in patients with good distal runoff. Because endovascular interventions are preferred by patients, can be repeated, and preserve the option of bypass surgery, PTA and stenting are increasingly employed for diffuse and complex SFA disease. Clarifying the role of PTA and stenting in the treatment of complex SFA disease will require future studies that stratify results by both lesion anatomy and treatment indication.

Angioplasty, Balloon↗
PubMed2006

Cryoplasty for the treatment of femoropopliteal arterial disease: extended follow-up results.

PURPOSE: To report the findings from a multicenter study of patients treated with cryoplasty who were then followed for an average of > 2 years post-treatment. METHODS: Extended clinical follow-up was obtained for 70 patients (45 men; mean age 70.5 +/- 8.8 years) who originally received cryoplasty therapy to treat symptoms of intermittent claudication as part of a multicenter investigational device exemption (IDE) study. For all subjects, cryoplasty was used to treat stenoses or occlusions < or = 10 cm in the femoropopliteal arteries. The original IDE study protocol enrolled 102 patients with a primary endpoint of target lesion patency at 9 months post-treatment. This collection of additional longer term follow-up data was initiated 2.5 years after the onset of study enrollment. RESULTS: Extended clinical follow-up ranged from 11 to 41 months (mean 31). The clinical patency rate (freedom from target lesion revascularization) calculated by the Kaplan-Meier method was 83.2% after the original follow-up period of 300 days. After > 3 years (1253 days), the clinical patency rate was well maintained at 75.0%. CONCLUSIONS: Long-term data indicate that cryoplasty is a durable therapy, with relatively low long-term restenosis rates compared to other endovascular treatment approaches.

Aged↗
PubMed2006

Limb salvage following laser-assisted angioplasty for critical limb ischemia: results of the LACI multicenter trial.

PURPOSE: To evaluate the effectiveness of laser-assisted angioplasty for patients with critical limb ischemia (CLI) who were poor candidates for surgical revascularization. METHODS: A prospective registry at 14 sites in the US and Germany enrolled 145 patients with 155 critically ischemic limbs; the patients were poor candidates for bypass surgery owing to inadequate target vessel or saphenous vein, prohibitive cardiac disease, or significant comorbidities (ASA class 4). Additional comorbid risk factors included diabetes in 66%, hypertension in 83%, previous stroke in 21%, and myocardial infarction in 23%. Endovascular treatment included guidewire traversal and excimer laser angioplasty followed by balloon angioplasty with optional stenting. RESULTS: Occlusions were present in 92% of limbs. A mean of 2.7+/-1.4 lesions were treated per limb; the total median treatment length was 11 cm (mean 16.2, range 0.2-123). Stents were implanted in 45% of limbs. Procedural success, defined as <50% residual stenosis in all treated lesions, was seen in 86% of limbs. At 6-month follow-up, limb salvage was achieved in 110 (92%) of 119 surviving patients or 118 (93%) 127 limbs. CONCLUSION: Excimer laser-assisted angioplasty for CLI offers high technical success and limb salvage rates in patients unfit for traditional surgical revascularization.

Aged↗
PubMed2005

Internet-based teleangiography: an indispensable tool for the interventional cardiologist.

Efficient and effective communication of specific patient information between referring and consulting physicians has become increasingly important with the need to evaluate a variety of treatment strategies, including coronary bypass surgery, coronary intervention, and medical therapy, without prolonging hospital stay. Until recently, the options available were either slow (mail or courier) or costly and cumbersome (hardware-based digital solutions). eMedcon, a new, easy-to-install Internet-based software solution described in this article, offers a quick and inexpensive solution to image digital cine transfer. eMedcon was tested at our institution, Washington Hospital Center, and was found to transmit images effectively and rapidly between physicians at any Internet-accessible site and Washington Hospital Center. Our data indicate that use of eMedcon led to an increase in repeat referrals and an increase in the number of physicians choosing to refer their patients to our institution.

Coronary Angiography↗
PubMed2005

Carotid artery stenting: update.

"Extracranial carotid artery stenosis is responsible for approximately 20-30% of ischemic strokes. Traditionally, carotid artery stenosis has been treated with carotid endarterectomy. However, the low periprocedural complication rate and the mid term durability of carotid artery stenting has made it a competitive alternative treatment strategy. This update reviews the technical aspects of carotid artery stenting, clinical data supporting carotid artery stenting-particularly in high risk patients, and the complications associated with carotid artery stenting."

Blood Vessel Prosthesis Implantation↗
PubMed2004

Usefulness of optical coherent reflectometry with guided radiofrequency energy to treat chronic total occlusions in peripheral arteries (the GRIP trial).

Optical coherent reflectometry, a forward-looking, fiberoptic-guided device was used in 72 patients to direct radiofrequency energy across the central intraluminal portion of 75 chronic total occlusions in peripheral arteries (iliac, femoral, and popliteal) that failed attempts with conventional guidewires. The system was successful in crossing 76% of the chronic total occlusions with no clinical perforations or distal embolizations, and complications consisted of a single dissection greater than or equal to grade C.

Aged↗
PubMed2004

Renal artery stenting using gadodiamide arteriography in patients with baseline renal insufficiency.

PURPOSE: To investigate whether a contrast agent containing gadodiamide can reduce the incidence of contrast-induced nephropathy associated with renal artery stenting in patients with preexisting renal insufficiency. METHODS: Between 1999 and 2002, gadodiamide-based arteriography was used in 20 patients (12 men; mean age 69 years) with significant baseline renal insufficiency (creatinine > or =1.7 mg/dL) undergoing renal artery stenting for > or =70% stenoses in 25 renal arteries. Baseline creatinine levels were compared to postprocedure and midterm follow-up levels. RESULTS: Procedural success was 100%. An average of 74 mL of gadodiamide contrast was used per case. Four patients received an additional 30 mL (mean) of iodinated contrast due to poor image quality with gadodiamide alone. There was no significant change in mean creatinine levels at discharge (2.9 mg/dL) compared to baseline (3.0 mg/dL, p=0.72). At midterm follow-up, mean creatinine levels (2.4 mg/dL) were significantly lower compared to baseline (p=0.004). CONCLUSIONS: Gadodiamide-based arteriography can be effectively used during RAS in patients with baseline renal insufficiency. This technique may enhance the renal-protective effect of renal artery stenting in this high-risk population with renal artery stenosis.

Aged↗
PubMed2004

The Angiomax Peripheral Procedure Registry of Vascular Events Trial (APPROVE): in-hospital and 30-day results.

BACKGROUND: High-risk patient characteristics and complexity of percutaneous peripheral intervention (PPI) procedures suggest a need for predictable and reliable anticoagulation. We undertook this study to assess the safety and efficacy of bivalirudin as the procedural anticoagulant in patients undergoing PPI of the renal, iliac, or femoral artery. METHODS: This was a prospective, open-label, single arm study inpatients undergoing PPI of the renal, iliac, or femoral vessels to assessbivalirudin as the sole procedural anticoagulant (0.75 mg/kg bolus/1.75 mg/kg/hr infusion). The primary endpoint was procedural success defined as residual stenosis < 20%. Secondary endpoints included ischemic events (death, myocardial infarction, unplanned revascularization, and amputation), and bleeding complications, as well as ACT values and times to sheath removal, ambulation, and discharge. RESULTS: 505 patients were enrolled at 26 sites. Procedural success was achieved in 95.0% of patients. Ischemic events were low (1.4%) and similar between vessel types. Protocol-defined major hemorrhage and TIMI major hemorrhage rates were 2.2% and 0.4%, respectively. Mean ACTs were similar among treatment groups (renal 353.8 seconds(s); iliac 335.9s, femoral, 343.5s). CONCLUSION: Bivalirudin provided consistent anticoagulation and similar outcomes in all vessel types treated at the dose tested. Ischemic and bleeding event rates were low, demonstrating the safe use of bivalirudin as a procedural anticoagulant in PPI.

Aged↗
PubMed2003

Intravascular ultrasound analysis of infarct-related and non-infarct-related arteries in patients who presented with an acute myocardial infarction.

BACKGROUND: Previous studies have reported diffuse destabilization of atherosclerotic plaques in acute myocardial infarction (AMI). METHODS AND RESULTS: We used intravascular ultrasound (IVUS) to assess 78 coronary arteries (38 infarct-related arteries [IRAs] with culprit and nonculprit lesions and 40 non-IRAs) from 38 consecutive AMI patients. IVUS analysis included qualitative and quantitative measurements of reference and lesion external elastic membrane (EEM), lumen, and plaque plus media (P&M) area. Positive remodeling was defined as lesion/mean reference EEM >1.0. Culprit lesions were identified by a combination of ECG, wall motion abnormalities (ventriculogram or echocardiogram), scintigraphic perfusion defects, and coronary angiogram. Culprit lesions contained more thrombus (23.7% versus 3.4% in nonculprit IRA plaques and 3.1% in non-IRA plaques; P=0.0011). Culprit lesions were predominantly hypoechoic (63.2% versus 37.9% of nonculprit IRA plaques and 28.1% of non-IRA plaques; P=0.0022). Culprit lesions were longer (17.5+/-10.1, 9.8+/-4.0, and 10.3+/-5.7 mm, respectively; P<0.0001), had larger EEM area (15.0+/-6.0, 11.5+/-5.7, and 12.6+/-5.6 mm2, respectively; P=0.0353) and P&M area (13.0+/-6.0, 7.5+/-3.7, 9.3+/-4.3 mm2, respectively; P<0.0001), smaller lumens (2.0+/-0.9, 4.1+/-3.1, and 3.4+/-2.5 mm2, respectively; P=0.0009), and more positive remodeling (79.4%, 59.0%, and 50.8%, respectively; P=0.0155). The frequency of plaque rupture/dissection was greater in culprit, nonculprit IRA, and non-IRA plaques in AMI patients than in a control group of chronic stable angina patients with multivessel IVUS imaging. CONCLUSIONS: Culprit plaques have more markers of instability (thrombus, positive remodeling, and large plaque mass); however, these markers of instability are not typically found elsewhere. This suggests that the vascular event in AMI patients is determined by local pre-event lesion morphologies.

Angina Pectoris↗
PubMed2002

Morphologic and angiographic features of coronary plaque rupture detected by intravascular ultrasound.

OBJECTIVES: This study was designed to report the clinical and angiographic correlates of plaque rupture detected by intravascular ultrasound (IVUS). BACKGROUND: Acute coronary syndromes result from spontaneous plaque rupture and thrombosis. METHODS: We report 300 plaque ruptures in 257 arteries in 254 patients. Plaque ruptures were detected during pre-intervention IVUS. Standard clinical, angiographic, and IVUS parameters were collected and/or measured. One lesion per patient was analyzed. RESULTS: Multiple ruptures were observed in 39 of 254 patients (15%), 36 in the same artery. Plaque rupture occurred not only in patients with unstable angina (46%) or myocardial infarction (MI, 33%), but also stable angina (11%) or no symptoms (11%). The tear in the fibrous cap could be identified in 157 of 254 patients; 63% occurred at the shoulder of the plaque and 37% in the center of the plaque. Thrombi were more common in patients with unstable angina or MI (p = 0.02) and in multiple ruptures (p = 0.04). The plaque rupture site contained the minimum lumen area (MLA) site in only 28% of patients; rupture sites had larger arterial and lumen areas and more positive remodeling than MLA sites. Intravascular ultrasound plaque rupture strongly correlated with complex angiographic lesion morphology: ulceration in 81%, intimal flap in 40%, thrombus in 7%, and aneurysm in 7%. CONCLUSIONS: Plaque ruptures occur with varying clinical presentations, strongly correlate with angiographic complex lesion morphology, may be multiple, and usually do not cause lumen compromise.

Angina Pectoris↗
PubMed2002

Incidence, morphology, angiographic findings, and outcomes of intramural hematomas after percutaneous coronary interventions: an intravascular ultrasound study.

BACKGROUND: Intramural hematomas during percutaneous coronary intervention (PCI) have not been well studied. METHODS AND RESULTS: We used intravascular ultrasound to determine the incidence, morphology, and clinical features of post-PCI intramural hematomas. In 905 patients with 1025 consecutive native coronary artery, non-in-stent restenosis lesions undergoing PCI, 72 hematomas were detected in 69 arteries in 68 patients. The incidence of intramural hematomas per artery was 6.7% (69 of 1025); 36% (26 of 72) involved the proximal reference artery, 18% (13 of 72) were confined to the lesion, and 46% (33 of 72) involved the distal reference artery. The entry site from the lumen into the hematoma was identified in 86% of hematomas (62 of 72) and had the appearance of a dissection into the media. Conversely, a re-entry site was identifiable in only 8% (6 of 72). The axial extension of the hematoma was distal in 63% and proximal in 37%. In 60% of the hematomas (42 of 72) the angiogram had the appearance of a dissection; in 11% (8 of 72), it appeared to be a new stenosis; and in 29% (22 of 72), no significant abnormality was detected. Non-Q-wave myocardial infarctions occurred in 26% of patients (17 of 65). In 3 patients, the creatine kinase-MB was not measured during the hospital stay. Repeat revascularization occurred in 2 patients in-hospital, 2 additional patients at 1 month, and 8 additional patients at 1 year. There were 3 sudden deaths at 1 year. CONCLUSIONS: Intravascular ultrasound identified intramural hematomas after 6.7% of PCIs. The mechanism appeared to be a dissection into the media where blood accumulated because of a lack of re-entry. A third of ultrasound-identified hematomas showed no angiographic abnormalities. There was a high rate of non-Q-wave myocardial infarction, need for repeat revascularization, and sudden death in patients with hematomas.

Angioplasty, Balloon, Coronary↗
PubMed2002

Prognostic value of cardiac troponin I elevation after percutaneous coronary intervention in patients with chronic renal insufficiency: a 12-month outcome analysis.

Serum cardiac troponin I (cTnI) is a highly specific marker for myocardial damage in patients with chronic renal insufficiency (CRI), unlike creatine kinase myocardial band fraction (CK-MB), which may be elevated in the absence of myocardial injury in patients with CRI. We studied 116 consecutive CRI patients (serum creatinine +/- 1.8 mg/dL, not on dialysis) with normal baseline cTnI levels who underwent successful percutaneous coronary intervention (PCI). Patients were divided into two groups: group 1, elevated postprocedural cTnI (n = 50), and group 2, normal cTnI (n = 66). Patients with elevated cTnI were older and had a higher incidence of postinfarction angina and lower creatinine clearance compared to patients who did not have cTnI elevation. Atheroablative devices (rotational and directional atherectomy and excimer laser coronary angioplasty) were more frequently used in group 1 patients (27.1% vs. 18.5%; P = 0.04). In-hospital mortality, cardiac mortality, and Q-wave myocardial infarction rates did not differ between the two groups. At 12-month follow-up, total mortality rates were significantly higher in group 1 (28.0% vs. 9.9%; P = 0.002). Multivariate analysis showed that cTnI was an independent predictor of late mortality (OR = 2.26; CI = 1.07-4.77; P = 0.03). Thus, in patients with CRI, elevated cTnI levels after successful PCI is an important predictor of poor long-term outcome. Our data suggest that patients with cTnI elevation > 3 times above normal values are particularly at higher risk.

Age Factors↗
PubMed2002

Complex endovascular treatment for critical limb ischemia in poor surgical candidates: a pilot study.

PURPOSE: To evaluate the effectiveness of complex endovascular treatment for limb salvage in patients with critical limb ischemia. METHODS: In a prospective study, 23 patients (13 men; mean age 70 +/- 11 years, range 44-87) with ischemic ulceration or gangrene of 25 lower limbs were enrolled at 4 sites to evaluate treatment with excimer laser recanalization followed by balloon angioplasty with optional stenting in the superficial femoral, popliteal, and/or tibial arteries. RESULTS: Multiple lesions (mean 3.1, range 1-8) were treated in most cases. Reduction of stenosis/occlusion to <50% was achieved in 22 (88%) limbs. Individual cases of vessel perforation, inability to cross the lesion, and excessive residual stenosis accounted for the 3 failures. Over a 6-month period, 4 patients died of cardiac comorbidity and 1 was lost to follow-up. Adverse events included 4 minor and 2 below-knee amputations, 4 secondary angioplasties, and 4 femorodistal bypasses. The mean wound area reduction was 70% at 3 months, increasing to 89% at 6 months. According to life table analysis, the limb salvage rate was 90% with bypass and 69% without in the successfully treated patients (corresponding intention-to-treat rates were 79% and 61%). CONCLUSIONS: Complex endovascular treatment combining laser debulking and angioplasty/stenting offers an alternative for patients with critical limb ischemia who lack good surgical options.

Adult↗