A randomized comparison between rotational and standard coronary angiography.

AIM: Selective coronary angiography is nowadays the gold standard in the definition of coronary anatomy as well as the basis for percutaneous coronary interventions. However, the diagnostic accuracy of coronary angiography can be reduced if the number of angiographic views is inadequate or if the operator does not select appropriate projections. Rotational angiography (RA) has been proposed as an alternative technique in order to provide a more complete definition of coronary anatomy reducing, at the same time, radiation exposure and contrast medium dose. METHODS: We randomly assigned 31 eligible patients, undergoing diagnostic cardiac catheterization, to RA (n=16) and traditional angiography (TA, n=15). Total procedural time, fluoroscopy time, number of cine-runs, X-ray dose and contrast medium volume were recorded in both groups. RESULTS: There were no statistically significant differences between groups in age (59+/-5.8 vs 62.8+/-9.6 years, P=ns), body mass index (26.7+/-3.5 vs 27.1+/-3.4 kg/m2, P=ns), total procedural time (20.6+/-6.6 vs 22.2+/-11.3 min, P=ns) and fluoroscopy time (3.9+/-1.5 vs 4.9+/-1.8 min, P=ns). On the contrary, number of cine-runs, X-ray dose and contrast medium volume were significantly lower in RA patients as compared with TA patients (6.2+/-1.2 vs 9.7+/-2.1, P<0.01; 530.6+/-271.6 vs 831.2+/-343.9 mGy, P<0.05; 76.9+/-22.4 vs 102.9+/-26.4 ml, P<0.01, respectively). CONCLUSIONS: RA is safe and effective in defining coronary anatomy, leading to a significant reduction in radiation exposure and contrast medium volume.

A comparison of coronary artery stenting with angioplasty for isolated stenosis of the proximal left anterior descending coronary artery: five year clinical follow up.

BACKGROUND: Stent implantation for isolated stenosis of the proximal left anterior descending coronary artery (LAD) with preserved left ventricular function has been found to have a better clinical and angiographic outcome at one year than balloon angioplasty (PTCA). OBJECTIVE: To establish whether those results are maintained at five year follow up. METHODS: Patients were followed at least every six months. For those who died during follow up, data were obtained from medical records. MAIN OUTCOME MEASURES: Freedom from death, non-fatal myocardial infarction, cerebrovascular accident, and repeated target lesion revascularisation. Secondary end points were revascularisation in a remote region and freedom from angina. RESULTS: Follow up was complete in all patients. At five years, the primary end point was reached more often by patients randomised to stent implantation than to PTCA (80% v 53%; odds ratio (OR) 0.29 (95% confidence interval (CI) 0.13 to 0.69); p = 0.0034). In the PTCA group, 35% of patients underwent target lesion revascularisation v 15% in the stent group (OR 0.33, 95% CI 0.13 to 0.80; p = 0.014). There was a trend towards increased mortality in the PTCA group than in the stent group (17% v 7%; OR 0.36, 95% CI 0.10 to 1.21; p = 0.098). No significant differences were found between PTCA and stent groups for non-fatal myocardial infarction (8% v 5%; OR 0.58, 95% CI 0.13 to 2.54; p = 0.46) or cerebrovascular accident (2% v 0%). CONCLUSIONS: In patients with isolated stenosis of the proximal LAD, a five year clinical follow up confirmed a better outcome in those treated with stenting than with PTCA.

Unstable angina and elevated c-reactive protein levels predict enhanced vasoreactivity of the culprit lesion.

BACKGROUND: Because plaque inflammation may modulate coronary vasomotion, the association between systemic levels of C-reactive protein (CRP) and coronary vasoreactivity was assessed in patients with stable or unstable angina. METHODS AND RESULTS: In 31 patients with stable angina and 23 patients with unstable angina undergoing coronary angiography, minimal luminal diameter (MLD) of the culprit lesion was measured by quantitative coronary angiography at baseline, during the cold pressor test (CPT), and after intracoronary administration of nitroglycerin (NTG) and expressed as percent change from baseline. MLD of patients with unstable angina exhibited a greater reduction during CPT and a greater increase after NTG than did patients with stable angina (-17+/-14% versus -5+/-12%, P=0.0013, and 34+/-25% versus 8+/-20%, P<0.001, respectively). According to preprocedural serum levels of CRP, 36 patients had normal (

Ischemic preconditioning during coronary angioplasty is preserved in elderly patients.

BACKGROUND: To establish whether the adaptation to ischemia observed in humans during percutaneous transluminal coronary angioplasty (PTCA) after repeated balloon inflations, i.e. a clinical correlate of ischemic preconditioning, is preserved in elderly patients. METHODS: We studied 53 consecutive patients undergoing successful angioplasty for an isolated stenosis of a major epicardial coronary artery. On the basis of age, patients were separated into terciles: patients in the lower and middle terciles were grouped together (Group 1, adult patients, n = 24, mean age 50 +/- 6 years) and compared with those in the upper tercile (Group 2, elderly patients, n = 29, mean age 68 +/- 3 years). Intracoronary electrocardiogram was obtained at the end of the first two balloon inflations. Collateral recruitment during repeated balloon inflations was assessed by using an intracoronary Doppler guide wire (23 patients) or by using an intracoronary pressure guide wire (30 patients). RESULTS: In Group 1, ST-segment changes during the second inflation were significantly less than those at the end of the first inflation (6 +/- 3 vs 13 +/- 5 mm, p < 0.001). Similarly, in Group 2, ST-segment changes during the second inflation were significantly less than those at the end of the first inflation (6 +/- 4 vs 13 +/- 6 mm, p < 0.001). In both groups, collateral recruitment did not change from the first inflation to the second inflation (p = 0.1). CONCLUSIONS: Our study confirms that adaptation to ischemia during repeated balloon inflations in the setting of PTCA is independent of collateral recruitment and, therefore, is mainly due to ischemic preconditioning. More importantly, our study indicates that ischemic preconditioning is preserved in elderly patients.

Beneficial impact of isoflurane during coronary bypass surgery on troponin I release.

BACKGROUND: Experimental studies indicate that isoflurane, a commonly used volatile anesthetic, mimics the cardioprotective effects of ischemic preconditioning, probably through ATP-sensitive K+ (KATP) channel activation. The aim of this study was to evaluate the impact of isoflurane during coronary bypass surgery (CABG) on troponin I release. MATERIAL AND METHODS: Forty consecutive patients with chronic stable angina and multivessel disease undergoing isolated CABG were randomized to a control (16 men and 4 women, aged 51 to 73 years, mean 62) or isoflurane (15 men and 5 women, aged 51 to 77 years, mean 65) group before aortic cross-clamping and cardioplegia. Serum levels of troponin I and creatine kinase (CK)-MB, as markers of ischemic injury, were obtained at 24 hours after CABG. Regional wall motion score and left ventricular ejection fraction (LVEF) at transthoracic echocardiography were assessed 5 days postoperatively. Comparisons between groups were performed in the entire population and, subsequently, in those patients with preoperative LVEF < 50%. RESULTS: There were no significant differences between isoflurane-treated patients and controls in cross-clamp time (49 +/- 14 vs 51 +/- 13 min, p = ns), peak values of troponin I (0.9 +/- 0.7 vs 1.4 +/- 1.3 ng/ml, p = ns) and CK-MB (62 +/- 27 vs 64 +/- 27 U/l, p = ns), or postoperative echocardiographic score (26 +/- 7 vs 22 +/- 5, p = ns) and LVEF (53 +/- 10 vs 55 +/- 7%, p = ns). When the comparisons were restricted to those patients with preoperative LVEF < 50%, at 24 hours the isoflurane-treated patients exhibited a smaller release of troponin I and of CK-MB than controls (1.1 +/- 0.7 vs 2.3 +/- 1.3 ng/ml, p = 0.03, and 39 +/- 10 vs 57 +/- 22 U/l, p = 0.04, respectively). CONCLUSIONS: Isoflurane reduces myocardial injury in patients with impaired left ventricular function undergoing CABG; thus, it can be safely used as an additional cardioprotective tool during routine CABG in high-risk patients with poor left ventricular function.

Coronary artery stent placement in patients with variant angina refractory to medical treatment.

We performed a prospective study to establish the efficacy of coronary stent placement in a highly selected group of patients with focal coronary artery spasm in whom anginal attacks could not be prevented by full medical therapy. The results of this study indicate that intracoronary stent placement may represent an alternative and feasible treatment for patients with vasospastic angina refractory to aggressive medical therapy.

Effects of naloxone on myocardial ischemic preconditioning in humans.

OBJECTIVES: We attempted to establish whether naloxone, an opioid receptor antagonist, abolishes the adaptation to ischemia observed in humans during coronary angioplasty after repeated balloon inflations. BACKGROUND: Experimental studies indicate that myocardial opioid receptors are involved in ischemic preconditioning. METHODS: Twenty patients undergoing angioplasty for an isolated stenosis of a major epicardial coronary artery were randomized to receive intravenous infusion of naloxone or placebo during the procedure. Intracoronary electrocardiogram and cardiac pain (using a 100-mm visual analog scale) were determined at the end of the first two balloon inflations. Average peak velocity in the contralateral coronary artery during balloon occlusion, an index of collateral recruitment, was also assessed by using a Doppler guide wire in the six patients of each group with a stenosis on the left anterior descending coronary artery. RESULTS: In naloxone-treated patients, ST-segment changes and cardiac pain severity during the second inflation were similar to those observed during the first inflation (12+/-6 vs. 11+/-7 mm, p = 0.3, and 58+/-13 vs. 56+/-12 mm, p = 0.3, respectively), whereas in placebo-treated patients, they were significantly less (6+/-3 vs. 13+/-6 mm, p = 0.002 and 31+/-21 vs. 55+/-22 mm, p = 0.008, respectively). In both naloxone- and placebo-treated patients, average peak velocity significantly increased from baseline to the end of the first inflation (p = 0.04 and p = 0.02, respectively), but it did not show any further increase during the second inflation. CONCLUSIONS: The adaptation to ischemia observed in humans after two sequential coronary balloon inflations is abolished by naloxone and is independent of collateral recruitment. Thus, it is due to ischemic preconditioning and is, at least partially, mediated by opioid receptors, suggesting their presence in the human heart.

Exercise-induced myocardial ischemia triggers the early phase of preconditioning but not the late phase.

The aim of the present study was to establish whether exercise-induced ischemia triggers the second window of protection in 15 patients with coronary artery disease undergoing 2 consecutive treadmill exercise tests and a third test 24 hours later. Our findings confirm that a first exercise-induced ischemic challenge induces the early phase of preconditioning but not the late phase, thus suggesting that either a late protective effect of preconditioning does not exist in the setting of demand ischemia or, if it exists, it must be weaker than the early protective effect.

Effects of K(ATP) channel blockade by glibenclamide on the warm-up phenomenon.

AIMS: The increased tolerance to myocardial ischaemia observed during the second of two sequential exercise tests, i.e. the warm-up phenomenon, has been proposed as a clinical model of ischaemic preconditioning. As ATP-sensitive K+ channels appear to be a mediator of ischaemic preconditioning in both experimental and clinical studies, the aim of this study was to investigate the role of K(ATP) channels in the warm-up phenomenon. METHODS AND RESULTS: Twenty-six patients with coronary artery disease were randomized to receive 10 mg oral glibenclamide, a selective ATP-sensitive K+ channel blocker, or placebo. Sixty minutes after glibenclamide or placebo administration, patients were given an infusion of 10% dextrose (8 ml x min(-1)) to correct glucose plasma levels or, respectively, an infusion of saline at the same infusion rate. Thirty minutes after the beginning of the infusions, both patient groups underwent two consecutive treadmill exercise tests, with a recovery period of 15 min to re-establish baseline conditions. Before exercise tests, blood glucose levels were similar in placebo and glibenclamide groups (96 +/- 10 vs 105 +/- 22 mg x 100 ml(-1), P=ns). After placebo administration, rate-pressure product at 1.5 mm ST-segment depression significantly increased during the second exercise test compared to the first (220 +/- 41 vs 186 +/- 29 beats x min(-1) x mmHg x 10(2), P<0.01), but it did not change after glibenclamide (191 +/- 34 vs 187 +/- 42 beats x min(-1) x mmHg x 10(2), P=ns), with a significant drug-test interaction (P=0.0091, at two-way ANOVA). CONCLUSIONS: Glibenclamide, at a dose previously shown to abolish ischaemic preconditioning during coronary angioplasty, prevents the increase of ischaemic threshold observed during the second of two sequential exercise tests. These findings confirm that ischaemic preconditioning plays a key role in the warm-up phenomenon and that in this setting is, at least partially, mediated by activation of ATP-sensitive K+ channels.

Phentolamine prevents adaptation to ischemia during coronary angioplasty: role of alpha-adrenergic receptors in ischemic preconditioning.

BACKGROUND: Experimental studies indicate that alpha-adrenergic receptors are involved in ischemic preconditioning. Their role in humans is unknown. METHODS AND RESULTS: Eighteen patients undergoing angioplasty for an isolated stenosis of the left anterior descending coronary artery were randomized to receive intravenous infusion of phentolamine or placebo during the procedure. Intracoronary ECG and cardiac pain were determined at the end of the first two balloon inflations. Average peak velocity in the contralateral coronary artery during balloon occlusion, an index of collateral recruitment, was also assessed by using a Doppler guide wire. In both phentolamine- and placebo-treated patients, average peak velocity significantly increased from baseline to the end of the first inflation (P<.01), but it did not show any further increase during the second inflation. In phentolamine-treated patients, ST-segment changes and cardiac pain severity during the second inflation were similar to those observed during the first inflation (13+/-9 versus 12+/-8 mm, P=NS, and 51+/-34 versus 54+/-32 mm, P=NS, respectively), whereas in placebo-treated patients, they were significantly less (6+/-4 versus 13+/-7 mm, P<.01, and 26+/-20 versus 49+/-22 mm, P<.05, respectively). CONCLUSIONS: The adaptation to ischemia observed in humans after two sequential coronary balloon inflations is abolished by phentolamine and is independent of collateral recruitment. Thus, it occurs due to ischemic preconditioning and is, at least in part, mediated by alpha-adrenergic receptors.

Effects of A1 adenosine receptor blockade on the warm-up phenomenon.

The increased tolerance to myocardial ischemia observed during the second of two sequential exercise tests, i.e. the warm-up phenomenon, has been proposed as a clinical model of ischemic preconditioning. Adenosine appears to be a mediator of ischemic preconditioning in both experimental and clinical settings. The purpose of this study was to investigate the role of A1 adenosine receptors in the warm-up phenomenon. A double-blind, placebo-controlled, cross-over design was used. Twelve patients with coronary artery disease and positive exercise test were randomized to receive either bamiphylline, a selective A1 adenosine receptor antagonist, or placebo, immediately prior to two consecutive treadmill exercise tests carried out on day 1. Then, on day 2 all patients underwent two consecutive exercise tests immediately after administration of the remaining treatment. During the first exercise test, bamiphylline, compared to placebo, increased the time to and rate-pressure product at 1.5 mm ST-segment depression (from 317 +/- 118 to 423 +/- 127 s, p < 0.05 and from 199 +/- 38 to 230 +/- 36 b/min.mmHg.10(2), p < 0.05, respectively). After both placebo and bamiphylline infusions, time to 1.5 mm ST-segment depression during the second exercise test was greater than that during the first test (445 +/- 121 vs 317 +/- 118 s, p < 0.001 and 483 +/- 128 vs 423 +/- 127 s, p < 0.05, respectively), as was rate-pressure product at 1.5 mm ST-segment depression (228 +/- 40 vs 199 +/- 38 b/min.mmHg.10(2), p < 0.01 and 253 +/- 42 vs 230 +/- 36 b/min.mmHg.10(2), p < 0.05, respectively). In conclusion, bamiphylline, at a dose able to increase ischemic threshold and exercise tolerance compared to placebo, does not prevent the warm-up phenomenon. These findings suggest that, in the setting of the warm-up phenomenon, A1 adenosine receptor blockade is insufficient to prevent ischemic preconditioning.

Acetylcholine-induced vasodilatation in the human peripheral circulation is independent of ATP-sensitive K+ channels and prostacyclin.

BACKGROUND: Both experimental and clinical studies have shown that the increase in regional blood flow induced by acetylcholine is not completely prevented by inhibitors of the synthesis of endothelium-derived nitric oxide. To establish the role of ATP-sensitive potassium (KATP) channels and prostacyclin in mediating acetylcholine-induced increase in peripheral blood flow in humans, we assessed the effects of acetylcholine on the iliac artery blood flow velocity before and after glibenclamide, an antagonist of KATP channels, or before and after acetylsalicylic acid, an inhibitor of prostacyclin production. MATERIAL AND METHODS: Seventeen patients without evidence of peripheral vascular disease and normal coronary arteries at angiography received intra-iliac incremental bolus injections of acetylcholine (0.2, 2, 20 and 50 micrograms) via a 5F femoral sheath, at the end of routine cardiac catheterization. All injections were repeated 90 minutes after oral administration of glibenclamide (10 mg) in 10 patients of 15 minutes after i.v. infusion of acetylsalicylic acid (1000 mg) in the remaining 7 patients. Right iliac artery blood flow velocity was measured by using an intravascular 0.014-in Doppler guidewire. RESULTS: Before glibenclamide or acetylsalicylic acid administration, acetylcholine infusion increased average peak velocity by 128% (p < 0.001) and by 121% (p < 0.001), respectively. After glibenclamide or acetylsalicylic acid the increases of average peak velocity during acetylcholine infusion (by 121%, p < 0.001, and by 121%, p < 0.001, respectively) were similar (p = ns) to those observed during the control infusion. CONCLUSIONS: In man acetylcholine-induced vasodilatation in the territory supplied by the iliac artery is not prevented by glibenclamide or acetylsalicylic acid, thus suggesting that it is independent of activation of KATP channels and prostacyclin release.

Mechanisms of the warm-up phenomenon.

The warm-up phenomenon, described in patients with coronary artery disease, refers to the improved performance following a first exercise test. The aim of this study was to investigate the causes of the warm-up phenomenon. Fifteen patients with coronary artery disease and positive exercise test were enrolled. Patients were off treatment throughout the study. They underwent two consecutive treadmill exercise tests according to the Bruce protocol, with a recovery period of 10 min to re-establish baseline conditions. A third exercise test was then performed 2 h later. Before the onset of ischaemia, the rate-pressure product for a similar degree of workload was similar during the first and second exercise test, while it was lower during the third test (P < 0.05). Time to 1.5 mm ST-segment depression during the second and third exercise test was greater than during the first test (454 +/- 133 and 410 +/- 161 vs 354 +/- 127 s, P < 0.01, respectively). Similarly, the time to anginal pain onset was increased during the second and third exercise tests, compared to the first test (356 +/- 208 and 310 +/- 203 vs 257 +/- 204 s, P < 0.01, respectively). In contrast, rate-pressure product at 1.5 mm ST-segment depression during the second test was higher than that during the first test (232 +/- 47 vs 210 +/- 39 beats.min-1.mmHg.10(2), P < 0.01), while in the third test it was similar to that during the first (209 +/- 43 beats.min-1.mmHg.10(2), P = ns). The warm-up phenomenon observed a few minutes after exercise is characterized by an increase of both time to ischaemia and ischaemic threshold; this adaptation to ischaemia may be due to an improvement of myocardial perfusion or to preconditioning. Conversely, the warm-up phenomenon observed a few hours after repeated exercise is characterized by an increase of time to ischaemia but not of ischaemic threshold and is caused by a slower increase of cardiac workload. Thus, the mechanisms of the warm-up phenomenon may be different, time dependent and related to previous training.