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Biomedical subjects

A S Kurbaan

Publications and source records attributed to A S Kurbaan.

At least 19 recordsLinked to original sources
PubMed2001

Difference in the mortality of the CABRI diabetic and nondiabetic populations and its relation to coronary artery disease and the revascularization mode.

In diabetics with coronary artery disease (CAD), there remains uncertainty as to whether revascularization by percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass surgery (CABG) is preferable. To address this, 4-year mortality and level of pre- and postrevascularization angiographic CAD (measured by a series of coronary scores) were compared between both diabetics and nondiabetics and between revascularization modes in the Coronary Angioplasty versus Bypass Revascularization Investigation population as a whole, and then substratified by diabetic status and then by procedure to which they were randomized. The 1,054 randomized subjects contained 125 diabetics (11.9%) who had significantly greater mortality than nondiabetics (RR 2.19, p = 0.001). Among diabetics or nondiabetics, there was no significant mortality difference between those randomized to PTCA versus those to CABG. Diabetics randomized to PTCA and those to CABG had higher mortalities than respective nondiabetics; the association reached significance only in the former (RR 2.41, p = 0.002). All subgroups had similar prerevascularization CAD. Postrevascularization residual CAD was consistently significantly greater in PTCA than in respective CABG subgroups. Most measurements of CAD were greater in diabetic than in nondiabetic subgroups, but none was significant. In the Coronary Angioplasty versus Bypass Revascularization Investigation, diabetics had double the mortality of nondiabetics; this difference was statistically significant both for the entire population and for those randomized to PTCA, but not for those randomized to CABG. Among diabetics or nondiabetics, there was no significant mortality difference between PTCA and CABG. The higher diabetic mortality was more likely related to more rapid disease progression than to greater postrevascularization disease.

Angioplasty, Balloon, Coronary↗
PubMed2001

The effect of adjusting for baseline risk factors and post revascularisation coronary disease on comparisons between coronary angioplasty and bypass surgery.

BACKGROUND: In CABRI at 1 year PTCA was associated with greater repeat revascularisation and angina (but not myocardial infarction or death). We determined whether adjusting for baseline risk factors and post revascularisation coronary disease offsets this disadvantage of PTCA. METHODS: In the CABRI population the crude association of revascularisation mode (i.e. PTCA or CABG) with four clinical outcome (i.e. mortality, myocardial infarction, repeat revascularisation and angina) was adjusted for the baseline risk factors using a logistic regression model for each clinical outcome. A number of measures of angiographic coronary disease were used to assess post revascularisation coronary disease. One at a time, each of these measures was added to each of the four outcome models, to adjust for post revascularisation coronary disease. RESULTS: Comparing adjusted and crude unadjusted association of PTCA with repeat revascularisation there was an increase from 12.8 (P<0.0005) (crude relative risk) to 16.7 (P<0.0005) (adjusted odds ratio), with angina, from 1.89 (P=0.001) to 1.98 (P<0.0019), and with mortality from 1.84 (P=0.092) to 2.15 (P=0.060). PTCA was not significantly associated with myocardial infarction, either crudely or after adjustment. CONCLUSION: Adjusting for baseline risk factors and post revascularisation coronary disease tended to strengthen rather than weaken associations between PTCA and 1 year mortality, repeat revascularisation and angina at 1 year.

Aged↗
PubMed2000

Relation between coronary artery disease, baseline clinical variables, revascularization mode, and mortality. CABRI Participants. Coronary Angioplasty vs. Bypass Revascularisation Investigation.

The Coronary Angioplasty vs. Bypass Revascularisation Investigation (CABRI) trial comparing percutaneous transluminal coronary angioplasty (PTCA) with coronary artery bypass grafting did not show a difference in mortality with either procedure. Nonrandomized studies suggest that coronary artery disease (CAD) severity and distribution influences outcome. In the present study we explored the effect of prerevascularization CAD on 1-year mortality in the CABRI population, while adjusting for other baseline variables. Of the 1,054 patients recruited, there were sufficient angiographic results to derive the CAD scores in 974 (92.4%). Of these 974, there were 32 deaths. A number of CAD scores, both weighted for proximal disease (Duke and Leaman) and nonweighted, were used. These scores were then cross-tabulated against mortality. Demographic and clinical variables were also cross-tabulated against mortality and used to derive an initial logistic regression model to predict mortality. The effect of adding each of the CAD scores to this initial model was then assessed. After inclusion of the CAD scores, the best model was: (1) presence of peripheral vascular disease (odds ratio [OR] 3.89, p = 0.0025), (2) previous cerebrovascular accident (OR 2.86, p = 0.043), (3) older age (OR 1.05, p = 0.039), (4) a higher Duke score (OR 2.84, p = 0.0061), and (5) having undergone PTCA (OR 2.12, p = 0.047). In the CABRI population, adjustment for baseline variables, including prerevascularization CAD, revealed significantly higher mortality in those who underwent PTCA than in those who underwent coronary artery bypass grafting.

Adult↗
PubMed2000

Determining the optimal pacing intervention rate for vasovagal syncope.

INTRODUCTION: In this study, patients with rate hysteresis pacemakers implanted for vasovagal syncope were re-studied using serial tilt testing to determine whether, once triggered, pacing was more effective if the intervention rate was higher than the standard rate. METHODS AND RESULTS: Twenty patients (mean age 55.4 years, range 23-81, 14 male) were studied, with randomisation to either initial standard rate (80-90 beats/min) intervention, or to initial high rate (120 beats/min) intervention. Although 18 of the 20 reported complete abolition of syncope since pacing, only 8 patients could be objectively assessed. The respective mean time to tilt down after symptom onset with standard and high rate intervention was 193+/-234s and 185+/-143s, (P>0.05). CONCLUSION: Repeat tilt testing was only of limited value in assessing the benefit of pacing. There was no advantage with high rate intervention in delaying the loss of consciousness (or intolerable symptoms) after the initial onset of symptoms.

Adult↗
PubMed2000

Cardioinhibition during tilt testing identifies patients who may benefit from pacing.

UNLABELLED: This study examined whether the various hemodynamic collapse patterns observed during tilt testing in patients with suspected neurocardiogenic syncope are relevant when planning therapy, particularly whether a predominantly cardioinhibitory response predicts a beneficial response from pacing. METHODS: The effects of temporary atrioventricular (A-V) sequential pacing were studied during tilt testing in 34 patients 48.2 +/- 18.5 years of age. The patient population was divided into a cardioinhibitory group (VASIS classes 2A and 2B) or mixed group (VASIS classes 1 and 3) according to their response to baseline tilt testing. The test was then repeated during A-V pacing with rate hysteresis. A positive response to A-V pacing was defined as a > or = 30-second increase between onset of symptoms and syncope, or mitigation of symptoms compared with the baseline tilt test. RESULTS: The study protocol was not successfully completed in three patients. Among the remaining 31 patients, a baseline cardioinhibitory response was observed in 17, and a mixed response in 14 patients. A-V sequential pacing was successful in 13 of 17 patients with a cardioinhibitory response versus 5 of 14 patients with a mixed response (P = 0.024). CONCLUSION: The presence of a predominantly cardioinhibitory collapse pattern (VASIS 2A and 2B) during baseline tilt testing doubled the likelihood of successful temporary A-V sequential pacing, and may identify patients with neurocardiogenic syncope most likely to benefit from permanent dual chamber pacing.

Blood Pressure↗
PubMed2000

Respiratory changes in vasovagal syncope.

INTRODUCTION: Respiratory changes accompany the cardiovascular changes during head-up, tilt test-induced vasovagal syncope. METHODS AND RESULTS: Using the 45-minute 60 degrees head-up Westminster protocol, 29 patients were studied (mean age 53.9+/-20.0 years; 19 females). Two groups resulted: tilt-induced vasovagal syncope positive and negative. The cardiorespiratory parameters blood pressure (BP), heart rate (HR), tidal volume, and minute volume were measured. Comparisons of the cardiorespiratory parameters were made within the positive group and negative group, and then between the two groups. There were 14 in the positive group and 15 in the negative group. Baseline measurements were normalized to 1.0. Comparing the late tilt periods between the positive and negative groups, there were differences in BP (P < 0.002), HR (P < 0.002), tidal volume (P < 0.05), and minute volume (P < 0.002). In the positive group comparing early with late intervals: BP 1.11+/-0.09 versus 0.49+/-0.17, P < 0.0001; HR 1.18+/-0.12 versus 0.85+/-0.35, P < 0.009; tidal volume 1.39+/-0.34 versus 2.17+/-1.00, P < 0.015; and minute volume 1.24+/-0.26 versus 3.3+/-2.03, P < 0.0025. There were no comparable cardiorespiratory changes in the negative group. CONCLUSION: There were significant differences in the respiratory and cardiovascular parameters measured between those who were positive and those who were negative for tilt-induced vasovagal syncope. Within the positive group, in addition to the falls in HR and BP, there were significant increases in minute volume and tidal volume during late tilt. This suggests that there may be a role for respiratory sensors in vasovagal syncope that may permit earlier and hence possibly more effective therapy for selected patients.

Adult↗
PubMed1999

Non-elective intra-coronary stenting: are the clinical outcomes comparable to elective stenting at 6 months?

The aim of this study was to compare prospectively the clinical outcome of patients treated with intra-coronary stents as a non-elective/bailout procedure for acute or threatened vessel closure, with those undergoing elective stenting at 6 months. Sixty-four patients (60.2+/-11.7 y) who underwent non-elective stenting for abrupt or threatened vessel closure and/or sub-optimal results were prospectively compared with 68 patients (62+/-10.0 y) who were stented electively. All patients had broadly similar pre-procedural clinical profiles. However, patients in the elective group had a higher incidence of previous PTCA (10.2% vs. 0%, P = 0.01) and bypass surgery (30.9% vs. 6.3%, P = 0.0003) compared with the non-elective group. A total of 158 stents (1.19 per patient) were implanted in 132 patients with a procedural success rate of 99.3%. At 6 months follow-up there was no statistical difference in the primary composite end-point of death, myocardial infarction and the need of repeat revascularisation (10.9% vs. 5.8%, P = 0.35) between the two groups. However, patients in the non-elective group showed a higher incidence of unstable angina compared with the elective group (25% vs. 1.4%, P = 0.0004). The findings of this study suggest that stents (single or multiple) can be effectively implanted in non-elective situations with no increase in the incidence of death, non-fatal myocardial infarction, and the need of repeat revascularisation at 6 months compared with elective stenting.

Aged↗
PubMed1999

Usefulness of tilt test-induced patterns of heart rate and blood pressure using a two-stage protocol with glyceryl trinitrate provocation in patients with syncope of unknown origin.

This study assesses the vasovagal collapse pattern changes, i.e, heart rate (HR) and arterial blood pressure (BP) with a 2-stage tilt-test protocol using glyceryl trinitrate (GTN) provocation. With use of the 45-minute 60 degrees head-up Westminster protocol, 102 consecutive patients were studied. Sublingual GTN 300 microg was given to those with a negative passive tilt. Heart rate and BP patterns were classified according to the Vasovagal International Study classification (VASIS) and then compared between those with a positive passive tilt and those with a positive tilt after having been given GTN. Twelve patients did not tolerate tilt testing, and 16 had a negative response despite taking GTN. Thirty-five patients (20 women and 15 men, mean age 45 +/- 21 years [mean +/- SD]) did not take GTN and 38 (26 women and 12 men, mean age 53 +/- 22 years) had positive passive test results. When comparing the VASIS classification between the 2 groups, results showed: type 1, mixed BP and HR decreased without severe bradycardia (31% [passive] vs 54% [with GTN], p = NS); type 2A, BP decreased before HR decreased (20% vs 22%, p = NS); type 2B, HR decreased before or coincident with BP (34% vs 8%, p = 0.003); type 3, BP decreased without HR decrease (9% vs 0%, p = NS); exception 1, chronotropic incompetence (0% vs 13%, p = 0.026); and exception 2, excessive HR increase (6% vs 3%, p = NS). Thus, GTN use increases frequency of positive results from 34% to 73%. Older people with chronotropic incompetence, who may benefit from pacing, were identified. In younger people there was an increase in those with cardioinhibition.

Administration, Sublingual↗
PubMed1999

Trials of angioplasty and surgery: CABRI.

The medium term (4-year post randomization) results from CABRI indicate that the principal difference between those randomized to coronary angioplasty and those to coronary surgery has been the much greater need for repeat revascularization in the former. A number of factors may play a role in the greater repeat revascularization rate post coronary angioplasty, these include coronary restenosis, residual coronary artery disease, coronary artery disease progression. In the longer term, graft failure in those who have undergone coronary surgery will be important, and it remains to be seen what the effect of this will be.

Angioplasty, Balloon, Coronary↗
PubMed1998

Impact of postangioplasty restenosis on comparisons of outcome between angioplasty and bypass grafting. Coronary Angioplasty versus Bypass Revascularisation Investigation (CABRI) Investigators.

Restenosis is a major limitation of percutaneous transluminal coronary angioplasty (PTCA). In this study, we assessed the impact of restenosis on PTCA with reference to coronary angioplasty bypass grafting (CABG). In the Coronary Angioplasty versus Bypass Revascularisation Investigation (CABRI) PTCA population, those who had restenosis were defined as those needing a second revascularization at a site revascularized at the initial procedure. The 1-year clinical outcome of the nonrestenotic group (n=437) was compared with those who underwent CABG (n=453). There was no difference in deaths. In the nonrestenotic PTCA group, the incidence of more infarctions was insignificant (relative risk [RR] 1.9, 95% confidence intervals [CI] 0.96 to 3.75, p=0.064), there was a much greater need for repeat revascularization (RR 8.6, CI 5.14 to 14.41, p <0.0005), and patients had a poorer angina status (RR 1.46, CI 1.01 to 2.13, p=0.046). Using 2 measures of coronary disease, the degree of pre- and postrevascularization disease was compared between groups. There were no differences in prerevascularization disease. However, using either measure, residual postrevascularization disease was more frequent in the nonrestenotic PTCA group. Restenosis only partially accounts for the greater morbidity seen after PTCA, compared with CABG, in multivessel disease. The greater likelihood of residual disease post-PTCA may contribute to this greater morbidity.

Adult↗
PubMed1998

Differential restenosis rate of individual coronary artery sites after multivessel angioplasty: implications for revascularization strategy. CABRI Investigators. Coronary Angioplasty versus Bypass Revascularisation Investigation.

BACKGROUND: Restenosis is a major limitation of angioplasty. In this analysis we assessed the effects of lesion site and quality of dilatation on restenosis rate in the Coronary Angioplasty versus Bypass Revascularization Investigation population who underwent angioplasty. METHODS: The angiographic quality of the successful angioplasty revascularization at each site was assessed, and the subsequent restenosis rate was determined. Restenosis was defined by the need for a second angioplasty at the initial site or by surgical coronary bypass grafting at or distal to the initial site. RESULTS: The restenosis rate was unaffected by quality of dilatation but was significantly more common in the proximal left anterior descending artery compared with other sites, whether or not optimal dilatation had been achieved (relative risk 2.0 and 1.9, respectively). CONCLUSION: Revascularization strategies in multivessel disease should consider the presence or absence of a proximal left anterior descending artery target. Furthermore in studies in which restenosis is an outcome of interest, an allowance should be made for the distribution of target disease.

Aged↗