Biomedical subjects

Jaap Hamburger

Publications and source records attributed to Jaap Hamburger.

5 recordsLinked to original sources

PubMed2007

Redefining the normal angiogram using population-derived ranges for coronary size and shape: validation using intravascular ultrasound and applications in diverse patient cohorts.

OBJECTIVES: To develop a method for quantitating coronary angiographic abnormalities of segmental size and shape (tapering) in comparison to gender- and segment-specific, population derived, normal values. BACKGROUND: In the absence of obvious focal stenoses, remodeling renders the angiogram insensitive to the presence of atherosclerosis and invalidates use of a "normal reference segment" for calculation of percent diameter stenosis. METHODS: Equations were created for detection of size/shape abnormalities of coronary angiographic segments. After validation using intravascular ultrasound (IVUS), the equations were applied to a cohort of segments judged to be completely normal by a panel of highly experienced, core laboratory technicians; and a cohort of patients judged by an experienced interventionalist to have completely normal coronaries. RESULTS: In patients assessed by core technicians, 53% (162/303) of males, 39% (209/538) of normal segments in males, 60% (56/94) of females, and 40% (81/205) of normal segments in females had quantifiable abnormalities. In patients with normal coronaries as judged by an experienced interventionalist, 100% of males (n = 14) and females (n = 19), 37% (67/182) of segments in males and 43% (105/247) of segments in females had abnormalities. The left main segment was most commonly abnormal. CONCLUSIONS: We propose a set of equations validated using IVUS and based on gender- and segment-specific normal values for coronary angiographic size and shape that markedly improves the sensitivity of the coronary angiogram for detection of abnormalities. The method should replace the unfounded practice of labeling coronary angiograms as "normal" based solely on the failure to detect focal stenoses.

Cohort Studies↗

PubMed2005

Proximal protection during saphenous vein graft angioplasty: the Kerberos embolic protection system.

Percutaneous intervention in the setting of aortocoronary saphenous vein graft disease is associated with a significant risk of distal embolization. Devices intended to minimize the clinical impact of embolization have primarily utilized distally placed occlusive balloons or filters. Although such systems are often effective, distal protection does have limitations. We report a novel proximal embolic protection and rinsing system intended to overcome some of these limitations.

Angioplasty, Balloon, Coronary↗

PubMed2004

Vascular responses at proximal and distal edges of paclitaxel-eluting stents: serial intravascular ultrasound analysis from the TAXUS II trial.

BACKGROUND: On the basis of brachytherapy experience, edge stenosis has been raised as a potential limitation for drug-eluting stents. We used serial intravascular ultrasound (IVUS) to prospectively analyze vessel responses in adjacent reference segments after implantation of polymer-controlled paclitaxel-eluting stents. METHODS AND RESULTS: TAXUS II was a randomized, double-blind trial with 2 consecutive patient cohorts that compared slow-release (SR) and moderate-release (MR) paclitaxel-eluting stents with control bare metal stents (BMS). By protocol, all patients had postprocedure and 6-month follow-up IVUS. Quantitative IVUS analysis was performed by an independent core laboratory, blinded to treatment allocation, in 5-mm vessel segments immediately proximal and distal to the stent. Serial IVUS was available for 106 SR, 107 MR, and 214 BMS patients. For all 3 groups, a significant decrease in proximal-edge lumen area was observed at 6 months. The decrease was comparable (by ANOVA, P=0.194) for patients in the SR (-0.54+/-2.1 mm2) and MR (-0.88+/-1.9 mm2) groups compared with the BMS (-1.02+/-1.9 mm2) group. For the distal edge, a significant decrease in lumen area was only observed with BMS (-0.91+/-2.0 mm2, P<0.0001); this decrease was significantly attenuated with SR (0.08+/-2.0 mm2) and MR (-0.19+/-1.7 mm2) stents (P<0.0001 by ANOVA). Negative vessel remodeling was observed at the proximal (-0.48+/-2.2 mm2, P=0.011) but not the distal edges of BMS and at neither edge of SR or MR stents. CONCLUSIONS: The marked reduction in in-stent restenosis with SR or MR stents is not associated with increased edge stenosis at 6-month follow-up IVUS. In fact, compared with BMS, there is instead a significant reduction in late lumen loss at the distal edge with TAXUS stents.

Coronary Restenosis↗

PubMed2004

Direct stenting with TAXUS stents seems to be as safe and effective as with predilatation. A post hoc analysis of TAXUS II.

BACKGROUND AND METHOD: Although direct coronary stenting does not improve angiographic outcome, it makes sense by reducing procedure times, radiation exposure and costs. Other potential advantages of direct stenting may be a reduction of myocardial ischemia time, which could be clinically relevant in high-risk patients. With the introduction of drug-eluting stents, however, concern arose that direct stenting would possibly damage the polymer coating and change or diminish the efficacy of the programmed drug release. Also, concerns about safety by preventing optimal apposition of single stent struts developed. It is the purpose of this paper to retrospectively analyze the data from the TAXUS-II Trial (536 patients) regarding patients with and without direct stenting. While predilatation was recommended per protocol, direct stenting was not forbidden: thus, direct stenting was performed in 49 patients (TAXUS n = 23, control n = 26). RESULTS: In the TAXUS groups, there was no significant difference regarding major adverse cardiac events (MACE; 7.5% vs. 4.3%), angiographic restenosis in the analysis segment (4.8% vs. 4.3%), late loss (0.28 +/- 0.36 vs. 0.33 +/- 0.30 mm) or intravascular ultrasound-(IVUS-)measured volume obstruction (7.95 +/- 9.84% vs. 5.61 +/- 7.91%) at six months between the predilated and directly stented patients. The same was true for the patients receiving the control stent. Compared with the directly stented control group, the statistically significant positive effects of TAXUS direct stenting were maintained, regarding angiographic restenosis in the analysis segment (4.3% vs. 30.8%), late loss (0.33 +/- 0.30 vs. 0.80 +/- 0.62 mm) or IVUS-measured volume obstruction (5.61 +/- 7.91% vs. 22.50 +/- 21.62%) at six months. MACE was reduced from 19.2% to 4.3%; due to the small number of patients this trend did not reach statistical significance. After predilatation, all parameters were significantly improved by the TAXUS stent. CONCLUSION: Comparison of patients receiving TAXUS stents with or without predilatation revealed no differences in clinical, angiographic or IVUS parameters at six months. This suggests that direct stenting with the polymer-based paclitaxel-eluting TAXUS stent is feasible, safe and equally effective. Randomized trials comparing stenting after predilatation versus direct stenting with drug-eluting stents are warranted.

Angioplasty, Balloon, Coronary↗

PubMed2000

Clinical and angiographic results with the NIR stent: First International NIR Endovascular Stent Study (FINESS-II).

BACKGROUND: Although safety and efficacy of the NIR trade mark stent have been reported, the long-term angiographic and clinical outcomes have yet to be investigated. The FINESS-II study (First International NIR Endovascular Stent Study) was designed to assess the procedural safety of single 9 and 16 mm NIR stent implantation, the six-month restenosis rate and finally the six- and 12-month clinical outcome of patients treated with this novel coronary stent. METHODS: Patients with angina and a single de novo lesion in a native coronary artery of >3 and <5 mm diameter were included in this multicentre, prospective, observational trial. Clinical follow-up was obtained at one, six and 12 months. Angiography was performed before and after the stent implantation and at six months. The primary endpoint included major adverse cardiac events (death, myocardial infarction and target lesion revascularization) within 30 days after the procedure. Major bleeding complications and subacute stent thrombosis within the first 30 days were also reported as specific endpoints. Secondary endpoints were major cardiac-event-free survival at six- and 12-month follow-up and angiographic restenosis at six months. RESULTS: A total of 156 patients (81% male, mean age 60 +/- 10 years), with stable (54%), unstable (40%) angina pectoris or silent ischemia (6%) were enrolled. The target vessel diameter was 2.94 +/- 0.54 mm. The minimal lumen diameter pre, post and at follow-up was 1.04 +/- 0.32 mm, 2.64 +/- 0.42 mm and 1.88 +/- 0.63 mm, respectively. Restenosis rate according to the >50% diameter stenosis criterion at six month follow-up was 19% (26/136). At 12 months, the event-free survival rate was 83% (two deaths, one Q-wave and three non-Q-wave myocardial infarctions, four bypass surgery and 17 target lesion revascularizations), while 87% of the patients were free of angina pectoris. CONCLUSION: the outcome of the FINESS-II trial is comparable to those observed in previous stent trials (Benestent II), indicating that the coronary NIR stent is safe and effective as a primary device for the treatment of native coronary artery lesions in patients with (un)stable angina pectoris.

Journal Article↗