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Biomedical subjects

Carlos Macaya

Publications and source records attributed to Carlos Macaya.

At least 91 records · Page 5Linked to original sources
PubMed2004

Basic assessment of paced activation sequence mapping: implications for practical use.

Some experiences support the use of atrial paced activation sequence mapping, but there is no systematic study assessing its spatial resolution, reproducibility, and influence of pacing parameters. The aim of this study was to evaluate these issues by using a 24-pole catheter positioned at the atrial aspect of the tricuspid and mitral annuli in 15 patients. Bipolar pacing was performed at two sites (right and left atria), 2 cycle lengths (300 and 500 ms) and two outputs (twice and tenfold the late diastolic threshold voltage for 2-ms pulses). The elapsed time between the atrial activation at the two dipoles adjacent to the pacing dipole (activation time [AT]) was measured during each pacing sequence. Changes in cycle length did not modify the AT. The increase in voltage slightly modified the AT (maximum -2 ms at the RA; 95% CI -3 to -1 ms) due to a greater shortening of the conduction time to the dipole located next to the anode. The 95% limits of the intraobserver and interobserver agreements in the AT measurement were -2 to 3 ms and -3 to 3 ms, respectively. The spatial resolution was studied in ten patients by measuring the AT during pacing from each dipole of a 20-pole catheter with a 1-3-1 mm interelectrode distance. The mean AT change was 10 +/- 4 ms per 6 mm of pacing site displacement (95% CI 8-11 ms, range 2.5-20 ms). In conclusion, paced atrial activation sequence analysis is reproducible, accurate, and relatively independent of pacing parameters.

Cardiac Pacing, Artificial↗
PubMed2004

Initial and follow-up results of the European Seaquence coronary stent registry.

The primary objective of the present study was to assess the feasibility and the safety of the Seaquence stent (CathNet-Science) deployment for the treatment of coronary artery disease and the event-free survival of patients treated with this coronary stent. The study was conducted as a multicenter, prospective, observational registry. Patients with stable or unstable angina pectoris who were candidates for percutaneous coronary intervention with elective stenting of one single de novo lesion in a native coronary artery > or =3 mm in diameter were included in the study. Clinical follow-up was performed at 1 month and 9 months. Major adverse coronary events (MACE), that is, cardiac death, myocardial infarction, and target vessel revascularization (re-PTCA or CABG), were recorded over a period of 9 months. Using this stent, a 99% in-hospital success rate was achieved. A total of 17 patients presented MACE (8.7%) during the whole follow-up period and target lesion revascularization was needed for 14 (7.1%) patients. Using multivariate analysis only some clinical parameters (patients treated for unstable angina, with a history of CABG or of female gender) were found as independent predictors of MACE after coronary stenting. Procedural related factors, angiographic characteristics, or reference diameter were not found to influence clinical outcome. Because the study was performed in patients with a high proportion of complex lesions (relative high-risk nonselected population with nearly one third calcified lesions, many long and type B2 and C lesions) we can conclude that the coronary Seaquence stent can be considered as a stent of reference in routine practice.

Adult↗
PubMed2004

[Is systematic use of drug-eluting stents justified? Arguments against].

Antiproliferative drug-eluting stents represent a miles tone in advances in interventional cardiology. The amount and quality of the scientific evidence now show these new stents to be highly effective in reducing neointimal proliferation, and hence the process of restenosis. Their clinical impact can be expected to become relevant in terms of both increased indications for angioplasty and the extent of stent usage. However, at this time the systematic use of drug-eluting stents for all patients is not considered justified, because of their limited availability, gaps in our knowledge of their safety, and because their unquestioned clinical benefits have been magnified by exaggerated reports of the clinical problem restenosis represents. Currently, the cost of these stents remains high, and the cost/benefit ratio for certain patients is unfavorable. For these reasons selective use of these new stents is considered more reasonable: they should be used only for those patients who will obtain, in absolute terms, the greatest clinical benefit.

Clinical Trials as Topic↗
PubMed2004

Negative predictive value of dipyridamole vs. dobutamine stress echocardiography in the long-term follow-up of patients undergoing major vascular surgery.

INTRODUCTION: Perioperative cardiovascular complications are a significant cause of post-surgical morbidity and mortality in patients undergoing major vascular surgery (MVS). Dobutamine stress echocardiography is the most important method of detecting coronary artery disease in these patients. Although dipyridamole stress echocardiography (SE-DIP) and dobutamine stress echo (SE-DOB) have demonstrated similar negative predictive value (NPV) in the early postoperative period in patients undergoing MVS, there are few data concerning the negative predictive value of SE-DIP in the long-term follow-up of this subgroup of patients. OBJECTIVE: Our aim was to compare the long-term NPV of these two types of stress echocardiography and to compare it with perioperative NPV, based on the working assumption that they are similar. PATIENTS AND METHODS: A retrospective study was made of 157 patients based on preoperative evaluations for vascular surgery between February 1997 and February 2000. Clinical history and the results of consecutive stress exams were analyzed. We excluded patients with a positive stress echo and those that performed dobutamine stress echo which was considered inconclusive since they did not reach 85% of the maximum heart rate for their age. Therefore, 110 patients were included, 29 (26.4%) with dobutamine and 81 (73.6%) dipyridamole-atropine. The patients were followed after surgery for a period of 2.2 +/- 1 years. Cardiac events were defined as cardiac death, nonfatal acute myocardial infarction and hospitalization for unstable angina. The cumulative probability of event-free survival was compared. RESULTS: The patients' mean age was 65 +/- 10 years, and 108 (98.1%) were men. After 2.2 +/- 1 years of follow-up, 7 cardiac events occurred in the group with negative SE-DIP (8.6%) and 3 in patients with negative SE-DOB (10.3%). There were no statistically significant differences between the two groups concerning event-free survival (3.7 +/- 0.2 vs. 3.5 +/- 0.2 years for SE-DIP and SE-DOB respectively; p = 0.91). Negative predictive values for SE for perioperative and long-term cardiac events were 97.3% and 90.9% respectively. CONCLUSIONS: SE-DIP is a good alternative to SE-DOB in the preoperative evaluation of patients undergoing MVS, with the NPV of SE-DIP being similar to SE-DOB in the perioperative period and in long-term follow-up.

Aged↗
PubMed2004

[Intravenous enalapril does not prevent tachycardia-induced acute atrial electrical remodeling].

INTRODUCTION AND OBJECTIVES: Recent clinical studies suggest a potential antiarrhythmic role of angiotensin-converting enzyme inhibitors in preventing atrial fibrillation. Studies in an animal model suggested that these drugs may prevent sustained atrial fibrillation by avoiding the occurrence of detrimental atrial electrical remodeling secondary to temporary episodes of fibrillation or atrial tachycardia. We sought to determine whether intravenous enalaprilat, administered at doses habitually used in clinical practice, prevented pacing-induced acute atrial remodeling. PATIENTS AND METHOD: We analyzed 16 patients with no structural heart disease referred for electrophysiologic study due to supraventricular tachycardia. During the control period, right and left atrial effective refractory periods (ERP) were determined before and after a 10-minute period of rapid atrial pacing (250 ms) to quantitatively assess pacing-induced shortening of the ERP. After full recovery, a bolus dose of enalaprilat (0.015 mg/kg) was infused and the measurement and stimulation procedure repeated to quantify remodeling after enalaprilat administration. RESULTS: In the control period, rapid pacing induced a significant 14% reduction (P<.01) in right atrial ERP and an 8% decrease (P<.01) in left atrial ERP as compared to baseline values. In the enalaprilat period, rapid pacing significantly reduced ERP by 15% in the right chamber (P<.01) and 7% in the left chamber (P<.01). There was no significant difference in the extent or time course of ERP shortening between the control and enalaprilat periods. The number of unintentionally induced atrial fibrillation episodes did not differ significantly between the two periods. CONCLUSIONS: Intravenous enalapril does not avoid the occurrence of pacing-induced acute electrical atrial remodeling, modify its time course, or impede the induction of atrial fibrillation.

Adult↗
PubMed2004

Platelet aggregation according to body mass index in patients undergoing coronary stenting: should clopidogrel loading-dose be weight adjusted?

BACKGROUND: A 300 mg clopidogrel loading-dose (LD) is widely used as an adjunct antithrombotic treatment to reduce the risk of thrombotic events early after coronary stenting (CS). Antithrombotic drugs commonly used during percutaneous coronary interventions, such as heparin and platelet glycoprotein IIb/IIIa inhibitors, but not clopidogrel LD, are weight-adjusted, and few data are available on which is the most effective clopidogrel LD regimen. The aim of this study was to assess whether body mass index (BMI) influenced platelet response to clopidogrel LD in patients undergoing CS. METHODS: Adenosine diphosphate (ADP)-induced platelet aggregation (PA) was assessed by light transmittance aggregometry in 48 patients on aspirin treatment undergoing CS receiving a 300 mg clopidogrel LD at intervention time. PA was assessed at baseline and up to 24 hours after intervention. Patients were divided into 2 groups according to BMI: overweight (BMI greater than or equal to 25 kg/m2; 29 patients) and normal weight (BMI<25 kg/m2; 19 patients). PA was significantly higher in overweight than in normal weight patients at baseline (60.1+/-18.6%; versus 47.6+/-13.5%; p=0.01), at 24 hours (42.3+/-18.4% versus 38.5+/-18.3%; p=0.02) and during the overall study time (p=0.025). Percentage of inhibition of PA 24 hours following clopidogrel LD was suboptimal (<40%) in 59% and 26% of overweight and normal weight patients, respectively (p=0.04). An elevated BMI was the only independent predictor of suboptimal platelet response. CONCLUSION: These data suggest that overweight patients may need a higher loading-dose of clopidogrel and/or an adjunct antithrombotic treatment to adequately inhibit platelet aggregation early after CS.

Aged↗
PubMed2004

Primary stenting of an anomalous left main trunk originating from the right coronary artery during acute myocardial infarction.

In 1.5 to 2.0% of patients with AMI referred for primary percutaneous coronary intervention, the left main trunk is identified as the culprit vessel. Among the congenital coronary anomalies, an anomalous origin of the left main trunk from the right sinus of Valsalva is very rare. A 73-year-old patient with lateral acute myocardial infarction was referred to primary angioplasty. The initial angiogram showed an anomalous origin of the left main from the right coronary artery, apparently with a septal course, with an angiographic image of intraluminal thrombus; in addition, a severe lesion was present at the distal right coronary artery. The left main and right coronary arteries were successfully treated with direct stenting. The subsequent clinical course during hospitalization was uneventful, and the patient was discharged alive.

Acute Disease↗
PubMed2004

Is a 300 mg clopidogrel loading dose sufficient to inhibit platelet function early after coronary stenting? A platelet function profile study.

BACKGROUND: Clopidogrel combined to aspirin reduces the early risk of stent thrombosis and a clopidogrel pre-treatment strategy is associated with a better outcome. However, in clinical practice such pre-treatment strategy is not always feasible and clopidogrel is frequently not administered until the time of intervention. Aim of the study was to compare platelet function profiles in patients undergoing coronary stenting receiving clopidogrel pre-treatment (75 mg x 2 daily at least 48 hours before intervention) compared to that of patients receiving a 300 mg loading dose at intervention time. METHODS: A total of 50 patients were included in whom patients' platelet aggregation (using light transmittance aggregometry) and platelet activation (P-selectin and PAC-1 expression by whole blood flow cytometry) were assessed following ADP stimuli at baseline, and 4 hours and 24 hours following coronary stenting. RESULTS: In the overall study population, 16/50 (32%) patients were pre-treated with clopidogrel and 34/50 (68%) received clopidogrel loading dose at intervention time. Platelet aggregation, as well as P-selectin and PAC-1 expression were significantly lower in clopidogrel pre-treated patients at baseline (p<0.001) and at 4 hours (p<0.01), while they were similarly inhibited 24 hours after intervention. In conclusion, platelet reactivity of patients treated with clopidogrel front loading at intervention time remains significantly higher than that of pre-treated patients in the early hours after coronary stenting. A higher loading dose at intervention time may be warranted to overcome the early risk of thrombotic complications.

Adenosine Diphosphate↗
PubMed2004

Impact of echocardiography in the short- and long-term prognosis of patients with infective endocarditis and negative blood cultures.

BACKGROUND AND AIM OF THE STUDY: Higher morbidity and mortality have been attributed to patients suffering endocarditis but with negative blood cultures. The study aim was to determine whether, in the present era of routine echocardiography, patients with negative-culture endocarditis had a worse short- and long-term outcome, and whether outcomes in patients with true negative and aborted positive blood cultures were different. METHODS: When endocarditis was clinically suspected, an early (<24 h) echocardiographic examination was performed in all patients, regardless of blood culture results. In total, 151 patients diagnosed with infective endocarditis (IE) comprised the study group. Among these patients, 40 (26%) had negative blood cultures, and 28 of this subgroup (70%) had received previous antibiotic therapy. Short- and long-term features and prognosis were compared between both groups. The combined main end-point was death or need for surgical repair. RESULTS: Similar anatomic and clinical characteristics were present among those patients with positive and negative cultures. In addition, mortality and need for surgery with regard to short- and long-term follow up of both groups was similar. There were no significant differences between patients with true- or aborted-negative cultures in terms of short- and long-term prognosis. CONCLUSION: No differences in short- and long-term prognosis were seen among patients with IE and positive versus negative blood cultures. The prognosis was also similar between those with true negative culture versus aborted negative cultures. Early echocardiography in patients with clinically suspected IE may have changed the outcome in patients with negative cultures.

Adult↗
PubMed2004

[Predictors of mortality following rescue percutaneous intervention].

INTRODUCTION AND OBJECTIVE: Rescue percutaneous transluminal coronary angioplasty (PTCA) is a mechanical reperfusion strategy aimed at achieving patency of the infarct-related artery after failed thrombolysis. However, in randomized studies the indication for rescue PTCA was per protocol rather than based on clinical criteria. The aim of this study was to determine predictors of mortality at 30 days following rescue percutaneous intervention. PATIENTS AND METHODS: Seventy-one consecutive patients who underwent rescue PTCA were included. Mean age was 61 (11) years, 80% were men and 9.8% had diabetes. RESULTS: The infarct-related artery was the left anterior descending artery in the 46.5%, and the mean percentage of stenoses was 91.0 (11.6)%. A stent was implanted in 97.2% and TIMI II-III flow was obtained in the 97.2% of the patients. Overall mortality was 9.8% at 30 days follow-up and 11.3% at 1 year follow-up. In the multivariate analysis, the independent predictors of mortality at 30 days were age (OR=1.2, 95% CI: 1.03-1.5, P=.001), Killip class III-IV (OR=20.1; 95% CI: 1.7-500; P=.003), PTCA failure (OR=indeterminate; P=.04) and left anterior descending artery involvement (OR=12.6; 95% CI: 0.7-214.9; P=.04). CONCLUSIONS: Rescue PTCA is effective in restoring blood flow in the infarct-related artery in the majority of patients in whom thrombolysis failed. The independent predictors of mortality were similar to those previously reported in acute myocardial infarction.

Angioplasty, Balloon, Coronary↗
PubMed2003

A randomized comparison of repeat stenting with balloon angioplasty in patients with in-stent restenosis.

OBJECTIVES: This randomized trial compared repeat stenting with balloon angioplasty (BA) in patients with in-stent restenosis (ISR). BACKGROUND: Stent restenosis constitutes a therapeutic challenge. Repeat coronary interventions are currently used in this setting, but the recurrence risk remains high. METHODS: We randomly assigned 450 patients with ISR to elective stent implantation (224 patients) or conventional BA (226 patients). Primary end point was recurrent restenosis rate at six months. Secondary end points included minimal lumen diameter (MLD), prespecified subgroup analyses, and a composite of major adverse events. RESULTS: Procedural success was similar in both groups, but in-hospital complications were more frequent in the balloon group. After the procedure MLD was larger in the stent group (2.77 +/- 0.4 vs. 2.25 +/- 0.5 mm, p < 0.001). At follow-up, MLD was larger after stenting when the in-lesion site was considered (1.69 +/- 0.8 vs. 1.54 +/- 0.7 mm, p = 0.046). However, the binary restenosis rate (38% stent group, 39% balloon group) was similar with the two strategies. One-year event-free survival (follow-up 100%) was also similar in both groups (77% stent vs. 71% balloon, p = 0.19). Nevertheless, in the prespecified subgroup of patients with large vessels (> or =3 mm) the restenosis rate (27% vs. 49%, p = 0.007) and the event-free survival (84% vs. 62%, p = 0.002) were better after repeat stenting. CONCLUSIONS: In patients with ISR, repeat coronary stenting provided better initial angiographic results but failed to improve restenosis rate and clinical outcome when compared with BA. However, in patients with large vessels coronary stenting improved the long-term clinical and angiographic outcome.

Aged↗
PubMed2003

Importance of diastolic fractional flow reserve and dobutamine challenge in physiologic assessment of myocardial bridging.

OBJECTIVES: This study reports a comparative assessment of the hemodynamic relevance of myocardial bridges (MB) using two modalities of fractional flow reserve (FFR), with and without concomitant inotropic challenge. BACKGROUND: Extravascular coronary compression by means of MB is modulated by myocardial inotropism and causes intracoronary systolic pressure overshooting and negative systolic gradients across the MB. The former characteristic suggests that adequate hemodynamic assessment of MB should include inotropic stimulation. The latter characteristic might interfere with FFR by decreasing the mean pressure gradient. METHODS: We compared the hemodynamic relevance of 12 lone MB in symptomatic patients using conventional (mean) and diastolic FFR. Diastolic FFR was obtained from post-processed, digitally acquired electrocardiogram and pressure signals. Previously validated cut off values of 0.75 (mean FFR) and 0.76 (diastolic FFR) for hemodynamic relevance were used. Measurements were performed at baseline and after incremental intravenous dobutamine doses. RESULTS: Fractional flow reserve decreased during dobutamine challenge: mean FFR was 0.90 +/- 0.04 at baseline and 0.84 +/- 0.06 after dobutamine (p = 0.0008); similarly, diastolic FFR was 0.88 +/- 0.05 and 0.77 +/- 0.10 before and after dobutamine, respectively (p = 0.0006). Diastolic FFR identified hemodynamic relevance in five patients, whereas mean FFR did so in only one patient. The discrepancy between mean FFR and diastolic FFR increased with dobutamine challenge: the ratio of mean FFR/diastolic FFR was 1.03 at baseline and 1.09 after dobutamine (p = 0.02). During the administration of dobutamine, the discrepancy was inversely related to the systolic pressure gradient (r = 0.58, P = 0.04). CONCLUSIONS: Physiologic assessment of MB should include dobutamine challenge. Because the overshooting of systolic pressure interferes with and is a cause of error in FFR measurements based on mean pressures, diastolic FFR appears to be the technique of choice for MB assessment, whereas mean FFR should be used with caution.

Adenosine↗
PubMed2003

Acute stent thrombosis after early withdrawal of platelet glycoprotein IIb/IIIa antagonists: potential rebound prothrombotic effect?

We report on two cases of acute coronary stent thrombosis after early withdrawal of different competitive inhibitors of the platelet glycoprotein IIb/IIIa receptor, eptifibatide and tirofiban. Differences in pharmacokinetics between different types of glycoprotein IIb/IIIa receptor blockers and a potential rebound prothrombotic effect with the use of these antiplatelet drugs are reviewed.

Acute Disease↗
PubMed2003

IL-1 cluster genes and occurrence of post-percutaneous transluminal coronary angioplasty restenosis: a prospective, angiography-based evaluation.

A polymorphic marker of the gene encoding the interleukin-1 (IL-1) receptor antagonist has been recently reported to be associated with risk of coronary artery disease. However, no prospective studies of the IL-1 gene cluster in relation to the occurrence of restenosis, a major complication of percutaneous transluminal coronary angioplasty (PTCA), have so far been conducted. We had the opportunity to investigate this question in a large, prospective cohort characterized by quantitative coronary angiography in all subjects. The IL1A A114S, IL1B -511C>T, IL1B 3953T>C, IL1RI exon1B T>C, and IL1RN VNTR (intron 2) polymorphisms were characterized in a cohort of 779 patients of whom 342 ("cases") had developed restenosis (as defined by >50% loss of lumen compared to immediate post-procedure results) at repeat angiography at 6 months post-PTCA. All observed genotype frequencies were in Hardy-Weinberg equilibrium. Frequencies for the rare alleles were: IL1A S, 0.29 (cases), 0.28 (controls); IL1B T, 0.31 (cases), and 0.33 (controls); IL1B C, 0.23 (cases), 0.24 (controls); IL1RI C, 0.34 (cases), 0.35 (controls); and IL1RN 2, 0.29 (cases), 0.29 (controls), respectively. There was no evidence for an association between genotype and restenosis or degree of lumen loss (adjusted for covariables). Our data indicate that the common variants in the IL-1 cluster genes are not associated with incidence of restenosis after PTCA.

Alleles↗
PubMed2003

Myocardial perfusion in real-time using power modulation. In vivo evidence for microcirculatory damage after acute myocardial infarction.

BACKGROUND AND OBJECTIVES: In addition to the myocardium, the microvasculature may be also damaged in acute myocardial infarction. The aim was to evaluate the capability of myocardial contrast echocardiography in the detection of microvasculature damage after myocardial infarction. PATIENTS AND METHODS: Twelve patients with recent acute myocardial infarction and five control subjects with normal coronary arteries and without history of myocardial infarction were studied. Myocardial contrast echocardiography with power modulation was performed, and quantitative data were measured off-line. Power modulation uses a combination of low (0.1) and high (1.7) mechanical indexes, allowing a real-time evaluation of myocardial perfusion. Contrast agent was administered as a 3-min bolus. The quantitative analysis was performed off-line by a different blinded investigator. The refilling velocity was calculated as the difference between the peak myocardial refilling value and the value at 1 s after the impulse divided by the time from the first second after the impulse to the peak refilling value. RESULTS: Eighty-one myocardial segments (75%) were analysed qualitatively and quantitatively in AMI patients, and 18 (60%) in control subjects (P=NS). The peak refilling intensity was not significantly different in patients and control subjects (6.62+/-5.85 vs. 7.53+/-4.06 dB, respectively). However, time to peak refilling intensity was significantly longer (5.25+/-1.57 vs. 4.00+/-0.53, P=0.004) and the velocity of refilling was significantly lower (2.74+/-5.34 vs. 6.58+/-8.02, P=0.028) in patients with myocardial infarction. CONCLUSION: There is microvasculature damage after myocardial infarction that is reflected as a delayed velocity of refilling in myocardial contrast echocardiography.

Adult↗