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K M Kent

Publications and source records attributed to K M Kent.

At least 37 records · Page 2Linked to original sources
PubMed2001

Are we making progress with percutaneous saphenous vein graft treatment? A comparison of 1990 to 1994 and 1995 to 1998 results.

OBJECTIVES: We sought to determine whether strategies to reduce procedural distal embolization and late repeat revascularization have resulted in more favorable outcomes after saphenous vein graft (SVG) angioplasty. BACKGROUND: Angioplasty of SVG lesions has been associated with frequent procedural and late cardiac events. Therefore, evolving strategies have been attempted to improve outcomes after SVG angioplasty. METHODS: We compared our earlier experience (1990 to 1994) of 1,055 patients with 1,412 SVG lesions with a recent group (1995 to 1998) of 964 patients with 1,315 lesions. RESULTS: Baseline characteristics were similar between the groups. However, there were significantly more unfavorable lesion characteristics (older, longer and significantly more degenerated SVGs) in the recent series. Between the two periods, there was decreased use ofatheroablative devices, whereas stent use increased. The procedural success rates (96.6% vs. 96.1%) were similar. However, one-year outcome (event-free survival) was significantly improved in the more recent experience (70.7% vs. 59.1%, p < 0.0001), especially late mortality (6.1% vs. 11.3%, p < 0.0001). Multivariate analysis showed stent use to be the only protective variable for both periods. CONCLUSIONS: This study shows that despite higher risk lesions, strategies to reduce distal embolization have maintained high procedural success. Late cardiac events, including mortality, have also been substantially reduced.

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PubMed2001

Vascular complications after percutaneous coronary interventions following hemostasis with manual compression versus arteriotomy closure devices.

OBJECTIVES: We evaluated the vascular complications after hemostasis with arteriotomy closure devices (ACD) versus manual compression after percutaneous coronary interventions (PCI). BACKGROUND: Previous clinical studies have indicated that ACD can be used for achievement of hemostasis and early ambulation after PCI. This study investigated the safety of ACD in achieving hemostasis after PCI compared with manual compression in a large cohort of consecutive patients. METHODS: A total of 5,093 patients were followed after PCI was performed with the transfemoral approach. Univariate and multivariate analysis were used to identify the predictors of vascular complications with ACD (n = 516) or with manual compression (n = 5,892) as a hemostasis option after sheath removal. RESULTS: The use of ACD was associated with a more frequent occurrence of hematoma compared with manual compression (9.3 vs. 5.1%, p < 0.001). There was also a higher rate of significant hematocrit drop (>15%) with ACD versus manual compression (5.2% vs. 2.5%, p < 0.001). Similar rates of pseudoaneurysm and arteriovenous fistulae were noted with either hemostasis technique. Vascular surgical repair at the access site was required more often with ACD versus manual compression (2.5 vs. 1.5%, p = 0.03). CONCLUSIONS: In this early experience with ACD after PCI, their use was associated with higher vascular complication rates than hemostasis with manual compression.

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PubMed2001

Treatment of focal in-stent restenosis with balloon angioplasty alone versus stenting: Short- and long-term results.

BACKGROUND: Although both percutaneous transluminal coronary angioplasty (PTCA) and additional stenting can be used for the treatment for focal in-stent restenosis (ISR), no large-scale comparative data on the clinical outcomes after these interventional procedures have been reported. METHODS: In the current study we compared the in-hospital and long-term clinical results of PTCA alone (n = 266 patients, n = 364 lesions) versus stenting (n = 135 patients, n = 161 lesions) for the treatment of focal ISR, defined as a lesion length less than or equal to 10 mm. RESULTS: There were significantly more diabetic patients in the PTCA group than in the stent group (36% vs 26%, P =.04), but other baseline characteristics were similar. Lesion length and preprocedure minimal lumen diameter (MLD) were also similar in the two groups, but the stent group had a larger reference vessel diameter (3.40 +/- 0.73 mm vs 2.99 +/- 0.68 mm, P <.001). Stenting achieved a larger postprocedure MLD than PTCA did (2.95 +/- 0.95 mm vs 2.23 +/- 0.60 mm, P <.001) and a smaller residual diameter stenosis (11% +/- 15% vs 23% +/- 16%, P =.04). Angiographic success was achieved in all cases. The rate of death/Q-wave infarction of urgent revascularization was higher with PTCA than with stent (5.6% vs 0.7%, P =.02). Postprocedure creatine kinase myocardial band enzyme elevation >5 times normal was more frequent with stent (18.5% vs 9.7%, P =.05). At 1 year the two interventional strategies had similar cumulative mortality (4.6% PTCA vs 5.1% stent, P not significant) and target lesion revascularization rate (24.6% PTCA vs 26.5% stent, P not significant). By multivariate analysis, the sole predictor of target lesion revascularization was diabetes (odds ratio 2.4, 95% confidence intervals 1.2-4.7, P =.01). CONCLUSION: Repeat stenting for the treatment of focal ISR had a higher postprocedure creatine kinase myocardial band elevation rate and similar long-term clinical results compared with PTCA alone.

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PubMed2001

The contribution of "mechanical" problems to in-stent restenosis: An intravascular ultrasonographic analysis of 1090 consecutive in-stent restenosis lesions.

OBJECTIVES: Serial intravascular ultrasonographic (IVUS) studies have shown that in-stent restenosis is the result of intimal hyperplasia (IH). However, routine preintervention IVUS imaging has suggested that many restenotic stents were inadequately deployed. The purpose of this IVUS study was to determine the incidence of mechanical problems contributing to in-stent restenosis (ISR). METHODS: Between April 1994 and June 2000, 1090 patients with ISR were treated at the Washington Hospital Center. All underwent preintervention IVUS imaging. IVUS measurements included proximal and distal reference lumen areas and diameters; stent, minimum lumen, and IH (stent minus lumen) areas; and IH burden (IH/stent area). RESULTS: In 49 ISR lesions (4.5%), there were morphologic findings that contributed to the restenosis. These were termed mechanical complications. Examples include (1) missing the lesion (eg, an aorto-ostial stenosis), (2) stent "crush," and (3) having the stent stripped off the balloon during the implantation procedure. Excluding mechanical complications, stent underexpansion was common. In 20% of the ISR cases the stents had a cross-sectional area (CSA) at the site of the lesion <80% of the average reference lumen area. Twenty percent of lesions had a minimum stent area <5.0 mm(2) and an additional 18% had a minimum stent area of 5.0 to 6.0 mm(2). Twenty-four percent of lesions had an IH burden <60%. CONCLUSION: Mechanical problems related to stent deployment procedures contribute to a significant minority of ISR lesions (approximately 25%).

Coronary Stenosis↗
PubMed2000

Effect of preintervention plaque burden on subsequent intimal hyperplasia in stented coronary artery lesions.

We sought to determine if axial and circumferential distribution of plaque before stenting determines the axial and circumferential distribution of subsequent intimal hyperplasia (IH). We studied 22 patients with a single Palmaz-Schatz stent implanted in a native coronary artery, who underwent intravascular ultrasound (IVUS) imaging before intervention, after stenting, and at 6-month follow-up. For each lesion, 7 locations were analyzed: proximal and distal reference, proximal and distal edge of the stent, proximal and distal location within the body of the stent, and the articulation. Pre- and postintervention and follow-up image slices were precisely aligned and analyzed for pre- and postintervention plaque area and follow-up IH area and thickness. The location of maximal IH area was at or adjacent to the location of maximal preintervention plaque in 17 of 22 of the patients (77%). Similiarly, the circumferential distribution of IH at follow-up paralleled the eccentricity pattern of the native plaque burden in 69% (24 of 35 slices). Using multivariant analysis, the strongest predictor of IH was preintervention plaque area (p = 0.001). IH accumulates axially and circumferentially preferentially at the site of maximal preintervention plaque.

Angioplasty, Balloon, Coronary↗
PubMed2000

Assessing a strategy of initial stand-alone extractional atherectomy followed by staged stent placement in degenerated saphenous vein graft lesions.

To assess whether a staged strategy (initial stand alone transluminal extraction atherectomy and coumadin therapy followed by stenting six weeks later) could reduce ischemic complications in degenerated saphenous vein graft (SVG) interventions, we studied 72 patients undergoing percutaneous interventions of degenerated SVG. Patients were divided into two groups; 28 were treated with a staged strategy (group I) and 44 with similar lesion characteristics were treated with a definitive initial procedure with transluminal extraction atherectomy +/- adjunctive balloon angioplasty and stenting (group II). Procedural success, major in-hospital complications (death, Q-wave myocardial infarction, and emergent coronary bypass surgery), and incidence of distal embolization were compared between the 2 groups. Procedural success was lower (92% vs 100%, p = 0.14) and major in-hospital complications were higher (0% vs 11%, p = 0.14) in group II. Distal embolization occurred in 11% of the patients in group I compared with 23% of the patients in group II (p = 0.19). At 6 week follow-up (group I), 9 patients (33%) had negative symptoms, 11 (41%) underwent stent implantation, 3 (11%) did not require any further therapy (without significant stenosis), and 4 (14%) had total occlusions. We therefore conclude that this staged strategy in degenerated SVG appears to reduce distal embolization but most importantly avoids major in-hospital complications, including any deaths either at the time of initial procedure or during the 6-week follow-up period.

Aged↗
PubMed2000

The prognostic implications of further renal function deterioration within 48 h of interventional coronary procedures in patients with pre-existent chronic renal insufficiency.

BACKGROUND: Acute deterioration in renal function is a recognized complication after coronary angiography and intervention. OBJECTIVES: The goal of this study was to determine the impact on acute and long-term mortality and morbidity of contrast-induced deterioration in renal function after coronary intervention. METHODS: We studied 439 consecutive patients who had a baseline serum creatinine > or = 1.8 mg/dL (159.1 /micromol/L) who were not on dialysis who underwent percutaneous coronary intervention in a tertiary referral center. All patients were hydrated before the procedure, and almost all received ioxaglate meglumine; 161 (37%) patients had an increase in serum creatinine > or = 25% within 48 h or required dialysis and 278 (63%) did not. In-hospital and out-of-hospital clinical events (death, myocardial infarction, repeat revascularization) were assessed by source documentation. RESULTS: Independent predictors of renal function deterioration were left ventricular ejection fraction (p = 0.02) and contrast volume (p = 0.01). In-hospital mortality was 14.9% for patients with further renal function deterioration versus 4.9% for patients with no creatinine increase (p = 0.001); other complications were also more frequent. Thirty-one patients required hemodialysis; their in-hospital mortality was 22.6%. Four patients were discharged on chronic dialysis. The cumulative one-year mortality was 45.2% for those who required dialysis, 35.4% for those who did not require dialysis and 19.4% for patients with no creatinine increase (p = 0.001). Independent predictors of one-year mortality were creatinine elevation (p = 0.0001), age (p = 0.03) and vein graft lesion location (p = 0.08). CONCLUSIONS: For patients with pre-existing renal insufficiency, renal function deterioration after coronary intervention is a marker for poor outcomes. This is especially true for patients who require dialysis.

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PubMed2000

Incidence, management, and outcome of coronary artery perforation during percutaneous coronary intervention.

We have analyzed the incidence, management, and outcome of 84 cases of coronary artery perforation in patients who underwent percutaneous coronary intervention at our institution. This complication was more frequent in female patients and in patients who underwent lesion modification with atheroablative devices. A total of 8 patients (9.5%) died after the procedure. They were usually older and had a higher incidence of cardiac tamponade; a larger percentage of these patients underwent emergency surgery than those who survived.

Adult↗
PubMed2000

Mechanism of lumen enlargement during intracoronary stent implantation: an intravascular ultrasound study.

BACKGROUND: Intravascular ultrasound analysis has assessed mechanisms of lumen enlargement after nonstent interventions, but not after stenting. METHODS AND RESULTS: Preintervention and postintervention intravascular ultrasound was used to study 25 de novo native coronary lesions treated with single MultiLink stents without preatheroablation. External elastic membrane, lumen, and plaque and media (P&M) areas were measured every 1 mm to include the lesion and reference segments that were 5 mm proximal and distal to it. Lesion mean lumen area increased from 4.0+/-1.0 mm(2) before the intervention to 8.8+/-2.0 mm(2) after the intervention (P<0.0001) as a result of an increase in mean external elastic membrane area (14. 2+/-2.7 to 16.1+/-3.0 mm(2), P<0.0001) and a decrease in mean P&M area (10.2+/-2.2 to 7.2+/-1.8 mm(2), P<0.0001). The decrease in lesion P&M was accompanied by an increase in both proximal reference mean P&M (7.0+/-1.9 to 8.4+/-2.0 mm(2), P<0.0001) and distal reference mean P&M (5.8+/-2.1 to 7.2+/-2.1 mm(2), P<0.0001). Volumetric analysis showed an axial redistribution of plaque away from the center of the lesion toward the reference segments to increase the plaque burden in both the proximal and distal reference segments. Total (lesion plus reference) mean P&M decreased from 8. 6+/-2.1 to 7.5+/-1.8 mm(2) (P<0.0001). CONCLUSIONS: The mechanisms of lumen enlargement after stenting involved (1) significant axial redistribution of plaque from the lesion into the reference segments, (2) vessel expansion, and (3) either plaque embolization or compression.

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PubMed2000

Treatment of in-stent restenosis with excimer laser coronary angioplasty versus rotational atherectomy: comparative mechanisms and results.

BACKGROUND: Atheroablation yields improved clinical results for balloon angioplasty (percutaneous transluminal coronary angioplasty, PTCA) in the treatment of diffuse in-stent restenosis (ISR). METHODS AND RESULTS: We compared the mechanisms and clinical results of excimer laser coronary angioplasty (ELCA) versus rotational atherectomy (RA), both followed by adjunct PTCA; 119 patients (158 ISR lesions) were treated with ELCA+PTCA and 130 patients (161 ISR lesions) were treated with RA+PTCA. Quantitative coronary angiographic and planar intravascular ultrasound (IVUS) measurements were performed routinely. In addition, volumetric IVUS analysis to compare the mechanisms of lumen enlargement was performed in 28 patients with 30 lesions (16 ELCA+PTCA, 14 RA+PTCA). There were no significant between-group differences in preintervention or final postintervention quantitative coronary angiographic or planar IVUS measurements of luminal dimensions. Angiographic success and major in-hospital complications with the 2 techniques were also similar. Volumetric IVUS analysis showed significantly greater reduction in intimal hyperplasia volume after RA than after ELCA (43+/-14 versus 19+/-10 mm(3), P<0.001) because of a significantly higher ablation efficiency (90+/-10% versus 76+/-12%, P = 0.004). However, both interventional strategies had similar long-term clinical outcome; 1-year target lesion revascularization rate was 26% with ELCA+PTCA versus 28% with RA+PTCA (P = NS). CONCLUSIONS: Despite certain differences in the mechanisms of lumen enlargement, both ELCA+PTCA and RA+PTCA can be used to treat diffuse ISR with similar clinical results.

Angioplasty, Balloon, Coronary↗
PubMed2000

Safety of intracoronary gamma-radiation on uninjured reference segments during the first 6 months after treatment of in-stent restenosis: a serial intravascular ultrasound study.

BACKGROUND: The effects of endovascular irradiation on uninjured reference segments during the treatment of in-stent restenosis are unknown. METHODS AND RESULTS: In the Washington Radiation for In-Stent restenosis Trial (WRIST), patients with in-stent restenosis were first treated with conventional catheter-based techniques and then randomized (blinded) to receive either gamma-irradiation ((192)Ir) or a placebo (dummy seeds). We identified all patients in whom the active (n=19) or dummy seeds (n=19) extended >10 mm proximal and distal to the in-stent restenosis lesion. Serial (postirradiation and follow-up) external elastic membrane (EEM), lumen, and plaque and media (EEM-lumen) areas were measured (using intravascular ultrasound) every 1 mm over 5-mm-long reference segments that were 6 to 10 mm proximal and distal to the in-stent restenosis lesion. During follow-up, a similar small increase occurred in the plaque and media area in the proximal and distal reference segments in both (192)Ir and placebo patients. However, in the (192)Ir patients, an increase in both proximal and distal EEM area occurred; as a result, no change in lumen area occurred. Conversely, in the placebo patients, the proximal reference EEM area decreased, and no change occurred in the distal reference EEM area; this contributed to a decrease in lumen area. CONCLUSIONS: There was no evidence of a deleterious effect of gamma-irradiation on angiographically normal uninjured reference segments in the first 6 months after the treatment of in-stent restenosis.

Coronary Disease↗
PubMed2000

Intracoronary gamma-radiation therapy after angioplasty inhibits recurrence in patients with in-stent restenosis.

BACKGROUND: Treatment of in-stent restenosis presents a critical limitation of intracoronary stent implantation. Ionizing radiation has been shown to decrease neointimal formation within stents in animal models and in initial clinical trials. We studied the effects of intracoronary gamma-radiation therapy versus placebo on the clinical and angiographic outcomes of patients with in-stent restenosis. METHODS AND RESULTS: One hundred thirty patients with in-stent restenosis underwent successful coronary intervention and were then blindly randomized to receive either intracoronary gamma-radiation with (192)Ir (15 Gy) or placebo. Four independent core laboratories blinded to the treatment protocol analyzed the angiographic and intravascular ultrasound end points of restenosis. Procedural success and in-hospital and 30-day complications were similar among the groups. At 6 months, patients assigned to radiation therapy required less target lesion revascularization and target vessel revascularization (9 [13.8%] and 17 [26.2%], respectively) compared with patients assigned to placebo (41 [63.1%, P=0.0001] and 44 [67.7%, P=0.0001], respectively). Binary angiographic restenosis was lower in the irradiated group (19% versus 58% for placebo, P=0.001). Freedom from major cardiac events was lower in the radiation group (29.2% versus 67.7% for placebo, P<0.001). CONCLUSIONS: Intracoronary gamma-radiation used as adjunct therapy for patients with in-stent restenosis significantly reduces both angiographic and clinical restenosis.

Aged↗
PubMed2000

Prognostic value of cardiac troponin-I levels following catheter-based coronary interventions.

This study has examined the prognostic significance of troponin-I (Tn-I) levels after catheter-based coronary interventions in coronary arteries and saphenous vein grafts lesions. Tn-I and creatine kinase-MB (CK-MB) fraction levels were measured at 6 and 18 to 24 hours after catheter-based coronary intervention in 1,129 consecutive patients with normal preintervention plasma levels of Tn-I, and CK-MB levels below the cutoff for myocardial infarction. Patients were stratified according to maximal postangioplasty Tn-I levels. Group I (n = 784) had no elevated Tn-I (<0.15 ng/ml), group II (n = 170) had Tn-I at 0.15 to 0.45 ng/ml, and group III (n = 175) had Tn-I elevation >0.45 ng/ml. Major in-hospital complications (death, 0-wave infarction, and emergent coronary bypass grafting) and out-of-hospital intermediate-term (8 months) outcomes were compared between the 3 groups. Tn-I elevation >0.45 ng/ml was associated with increased risk of mortality (group III, 1.6%; group II, 0.6%; and group I, 0.1%; p = 0.019) and major in-hospital complications (3.2%, 1.7%, and 0.5%; p = 0.004). There was no difference in death (1.8%, 3.2%, and 2.4%; p = 0.74), Q-wave infarction (0.6%, 0%, and 0.3%; p = 0.66), or target lesion revascularization (10.1%, 9.0%, and 9.3%; p = 0.86) between the 3 groups at follow-up. Cardiac event-free survival was similar between groups (p = 0.3). By multivariate analysis, Tn-I >0.45 ng/ml was an independent predictor for major in-hospital complications (odds ratio 2.1, 95% confidence interval 1.2 to 3.9, p = 0.01). The degree of risk was also associated with the conjoint elevation of Tn-I and CK-MB levels (odds ratio 1.1, 95% confidence interval 1.02 to 1.2, p = 0.01). We conclude that Tn-I levels >3 times the normal limit and conjoint elevation of Tn-I and CK-MB levels after coronary angioplasty are associated with increased risk of major in-hospital complications, but have no incremental risk of adverse intermediate-term (8 months) clinical outcomes.

Aged↗
PubMed2000

Percutaneous revascularization of the internal mammary artery graft: short- and long-term outcomes.

OBJECTIVES: We evaluated the short- and long-term clinical outcomes after percutaneous revascularization of the internal mammary artery (IMA) graft. BACKGROUND: Previous reports in a relatively small number of patients have indicated the safety of balloon angioplasty for the treatment of stenoses in the IMA graft. However, the use of alternative interventional techniques and their long-term results have not yet been evaluated. METHODS: We analyzed the in-hospital and one-year clinical outcomes of 174 consecutive patients who underwent percutaneous revascularization of 202 lesions located in the IMA graft, by either balloon angioplasty or stenting. RESULTS: Anastomotic lesions were evident in 128 cases (63%), and they were more commonly treated with balloon angioplasty (116/128, 91%), whereas lesions located at the ostium (n = 16, 8%) were more frequently treated with stents (11/16, 69%). Procedural success was 97% with excellent in-hospital outcome: 0.6% mortality rate, no Q-wave myocardial infarction (MI) and 0.6% rate of urgent bypass surgery. Cumulative one-year rates were: mortality 4.4%, MI 2.9% and target lesion revascularization (TLR) 7.4%. CONCLUSIONS: Revascularization of the IMA graft can be performed safely, with high procedural success and a low rate of in-hospital complications. Long-term follow-up showed very low TLR rate.

Adult↗