Biomedical subjects

J M Lablanche

Publications and source records attributed to J M Lablanche.

At least 109 records · Page 6Linked to original sources

PubMed1993

Response of human coronary arteries to serotonin after injury by coronary angioplasty.

BACKGROUND: Atherosclerotic stenoses that have exaggerated vasomotor responses are especially prone to restenosis after coronary angioplasty. Experimental studies show that vasomotor responses in normal vessels are altered by acute mechanical injury, an alteration that in part reflects changes in the functional characteristics of endothelium that has regenerated after injury. METHODS AND RESULTS: We examined, by quantitative coronary arteriography, the response of dilated and control coronary segments to intracoronary infusions of graded doses of serotonin, an endothelium-dependent vasoactive agent, and to intracoronary injection of isosorbide dinitrate, an endothelium-independent smooth muscle dilator in 15 patients who had undergone a single percutaneous transluminal coronary angioplasty procedure and who had no clinical features of variant angina. Dose-dependent constriction to serotonin occurred at all measured sites. The mean +/- SEM diameter reductions, expressed as percent reduction in baseline diameter that was observed at proximal (18.1 +/- 2.9, 18.8 +/- 2.2) and distal (30.9 +/- 4.4, 35.4 +/- 5.3) control sites in the dilated and nondilated vessels, respectively, at the highest dose, were similar. The degree of constriction in distal segments was significantly (P < .01) greater than that in proximal segments. Total or subtotal occlusion occurred at the angioplasty site in 4 patients at the highest infused dose (10(-4) mol/L). The mean percent reduction in baseline diameter at previously dilated sites (53.8 +/- 5.9) at this dose was significantly (P < .05) greater than that observed at the adjacent proximal control sites and similar to that observed at distal control sites. All segments dilated significantly after intracoronary injection of isosorbide dinitrate. CONCLUSIONS: In dilated and nondilated vessels, serotonin caused significantly more marked constriction in distal than in proximal vessel segments. In dilated vessels, the vessel segments that had been subjected to angioplasty had a constrictor response to serotonin that was more marked than at adjacent proximal control sites and equivalent to that in the distal vessel segments. This enhanced constrictor response could be related to changes in endothelial cell function after regeneration or to hyperreactivity of smooth muscle cells at the angioplasty site.

Adult↗

PubMed1993

[Evaluation of the anesthetic risk in patients with coronary disease prior to non-cardiac surgery].

Evaluation of operative risk in coronary artery disease patients before non-cardiac surgery is a frequent problem concerning 100,000 patients each year in France. Perioperative cardiac morbidity is the first cause of death associated with non-cardiac surgery, with infarction rates of the order of 1 to 2% in coronary disease patients. These infarcts are followed by the death of the patient in 25 to 50% of cases. Evaluation of anesthetic risk is based upon three points: type of surgery, clinical findings and results of investigations. The risk is markedly increased in emergency surgery, and in thoracic, intraperitoneal and above all vascular surgery, in particular when clamping of the aorta is involved. From a clinical standpoint, only a history of infarction and signs of peripheral cardiac failure are independent predictive factors of postoperative complications. Other criteria, e.g. age, uncontrolled hypertension, diabetes and above all the severity of angina are also associated with the onset of perioperative-complications. This evaluation can be refined by electrocardiogram (Q wave, ST segment anomalies, ventricular hypertrophy and left bundle branch block) and chest X-ray. The usefulness and predictive value of exercise tests, when possible in a preoperative context, are particularly precious when the result is positive at low work-load. Many publications have studied the value of myocardial isotope scan, in particular before vascular surgery. They report the excellent negative predictive value (95 to 100%) of this investigation. Furthermore, the predictive value of isotope scan is all the greater when the clinical risk factors seen in the patients and the number of areas with ischemia are taken into account.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗

PubMed1993

[Should moderate coronary stenosis be dilated in patients with multi-vessel disease?].

This study evaluated the frequency of coronary angioplasty of non-significant (< 50%) stenoses during procedures of multiple revascularisation, and also determined the angiographic outcome of these dilatations at 6 months. All coronary lesions were assessed by quantitative angiography before and after angioplasty and at the 6 month control examination. In a population of 696 patients undergoing angioplasty of at least two coronary segments, 29 had a stenosis of < 50%. Angiographic control at 6 months was obtained in 26 of these patients (90%), corresponding to 61 coronary stenoses 29 of which were not significant (< 50%) (Group 1), and 32 of which were significant (Group 2) before angioplasty. By definition, before angioplasty, the lesions in Group 1 were less severe than in Group 2 (41.8 +/- 6.6% versus 65.9 +/- 9.6% respectively, p < 0.0001). After angioplasty, the degree of stenosis was comparable in the two groups (30.7 +/- 9.4% and 33 +/- 10.4%). At the 6 month control angiography, the percentage stenosis of the lesions in Group 2 (39.7 +/- 16%) remained significantly lower than before angioplasty (p < 0.0001). Six of these lesions (19%) developed restenosis. In Group 1, the percentage stenosis at control (39.5 +/- 18%) was comparable to that before angioplasty. Moreover, 5 lesions in Group 1 (17%) which were initially non-significant had > 50% stenosis at the 6 month control. These results show that dilatation of non-significant coronary stenosis during multiple revascularisation procedures is not common and should be avoided. Not only is there no benefit at 6 month control angiography but also the procedure may accelerate the evolution of the atherosclerosis.

Aged↗

PubMed1993

[Restenosis after coronary angioplasty. Contribution of experimental models].

Restenosis is the main complication of coronary angioplasty. Many experimental models have been developed over the last few years, reflecting very active research work in this field. The value of experimental models may be discussed under two headings: improvement in our understanding of the mechanisms of restenosis and the development of preventing strategies. The smooth muscle cell is the main cause of restenosis, experimental models having demonstrated a triple response which has been observed clinically: proliferation, migration to the intima and synthesis of the extracellular matrix. The mechanisms controlling this response are not fully understood, the most likely candidates being desendethelialisation, platelets and other circulating components of the blood, vasopressive hormones especially the renin-angiotensin system, growth factors and finally the degree of direct trauma to the smooth muscle cells. Experimental models also allow evaluation of therapeutic strategies elaborated to reduce the frequency of restenosis in clinical practice: three strategies are identifiable: systemic treatment, local treatment and genetic therapy. At the present time, none of these approaches has been clearly shown to be effective clinically though some positive results have been observed in the animal.

Angioplasty, Balloon, Coronary↗

PubMed1993

[Myocardial revascularization in silent myocardial ischemia].

Although there have been many reports of medical treatment of silent myocardial ischaemia (SMI) there have been fewer studies on the effects of myocardial revascularisation for this form of ischaemia. Myocardial revascularisation by coronary bypass surgery is particularly beneficial in patients with triple vessel disease and poor ventricular function, as shown by Weiner in a subgroup of patients from the CASS study. The tendency nowadays is to offer percutaneous transluminal coronary angioplasty (PTCA), because it is less traumatic, relatively simple and effective. A review of the literature shows that SMI may be treated effectively by PTCA. In a personal series of 62 patients, 80% of those are still asymptomatic and have no signs of ischaemia on maximal negative exercise stress tests one year after the procedure.

Angioplasty, Balloon, Coronary↗

PubMed1993

[Angiography of the left ventricle].

Left ventricular angiography in the 30 degree right anterior oblique projection is the reference method of calculating volumes and assessing segmental wall motion. The calculation of volumes is based on the surface-length or Simpson's methods which assume that the ventricle has an ellipsoid shape. The use of both the right and left anterior oblique projections only slightly improves the accuracy of the method and is not necessary in routine procedures. The global parameters of left ventricular function are the end-systolic and end-diastolic volumes and the ejection fraction. Segmental wall motion assessment provides a more precise analysis of left ventricular function. Many methods have been described but only two have been validated clinically: the Stanford method proposed by Ingels in which fractional shortening is calculated with respect to a point situated at 69% of the length of the axis between the apex and the anterior aortic border, and the more complex Rotterdam method reported by Slager. The introduction of digitisation of the image has enabled calculation of these different parameters in routine investigations.

Angiography↗

PubMed1992

Prognostic value of changes in R-wave amplitude during exercise testing after a first acute myocardial infarction.

To investigate the prognostic value of exercise-induced changes in R-wave amplitude and their relation to other exercise and angiographic variables, 303 consecutive patients who underwent maximal exercise testing and coronary angiography within 2 months of a first acute myocardial infarction were studied. R-wave amplitude at peak exercise increased or was unchanged in 159 patients (57.4%) and decreased in 118 (42.6%). Increased R-wave amplitude was significantly related to underlying 3-vessel disease (p = 0.0001), the extent of ST-segment depression on exercise (p = 0.0001), and the time to 1 mm ST depression (p less than 0.05). Follow-up information was available in 285 patients (86.4%) at a mean of 4 +/- 1.8 years. Death from cardiac causes occurred in 25 patients (9%); 18 (6.5%) developed recurrent myocardial infarction, and 32 (11.6%) developed angina. Variables with a predictive value for cardiac death were maximal exercise heart rate (p = 0.0005), occurrence of exercise-related supraventricular arrythmia (p = 0.02), and number of diseased vessels (p = 0.02). R-wave changes had no predictive value. No variable had a predictive value for recurrent infarction. Maximal exercise heart rate (p = 0.02) and increased R-wave amplitude (p = 0.0001) were significantly related to the occurrence of angina at follow up. Exercise-related R-wave increases were associated with the presence of angina at follow-up, but had no predictive value for cardiac death or recurrent infarction; their association with subsequent angina appears to reflect an association with more severe underlying coronary disease.

Angina Pectoris↗

PubMed1992

Percutaneous transluminal coronary rotary ablation with Rotablator (European experience).

This study reports the results from 3 European centers using rotary ablation with Rotablator, a device that is inserted into the coronary artery and removes atheroma by grinding it into millions of tiny fragments. Rotary ablation was performed in 129 patients. Primary success (reduction in percent luminal narrowing greater than 20%, residual stenosis less than 50%, without complications) was achieved by rotary angioplasty alone in 73 patients (57%). An additional 38 patients (29%) had successful adjunctive balloon angioplasty. Thus primary success was achieved in 111 patients (86%) at the end of the procedure. Acute occlusion occurred in 10 patients (7.7%). Recanalization was achieved by balloon angioplasty in 7: urgent bypass grafting was undertaken in 2. Q-wave and non-Q-wave myocardial infarction occurred in 3 and 7 patients, respectively. No deaths occurred. Follow-up angiography was performed in 74 patients (60%). Restenosis, defined as the recurrence of significant luminal narrowing (greater than 50%) occurred in 17 of 37 patients (46%) who underwent rotary ablation alone, and 11 of 37 patients (30%) who had adjunctive balloon angioplasty. The overall angiographic restenosis rate was 37.8%. In conclusion, rotary ablation is technically feasible, and relatively safe in the coronary circulation. The low primary success rate reflects the limited size of the device, which can be introduced through available guiding catheters, and limits the use of rotary ablation as a stand-alone procedure to lesions in small arteries or in distal locations. No reduction in restenosis was seen, but the role of this device combined with balloon angioplasty in larger arteries needs to be further defined.

Adult↗

PubMed1992

Clinical characteristics and angiographic follow-up of patients undergoing early or late repeat dilation for a first restenosis.

OBJECTIVE: The aim of this study was to analyze the angiographic rate of recurrent restenosis in patients who underwent repeat coronary angioplasty for a first restenosis within 3 months or greater than 3 months after the first procedure. BACKGROUND: Several studies that have examined risk factors for restenosis after coronary angioplasty have suggested that a short interval between a first angioplasty and a repeat procedure is associated with an increased risk for a second restenosis. METHODS: Between January 1981 and December 1990, 423 patients underwent a repeat coronary angioplasty procedure because restenosis had occurred at the site of a successful first angioplasty procedure. The clinical characteristics, immediate outcome and angiographic rate of recurrent restenosis were compared in patients who underwent repeat dilation within 3 months (early redilation group, n = 77) or greater than 3 months (late redilation group, n = 346) after the first procedure. RESULTS: The incidence of unstable angina at the time of the repeat procedure was significantly higher in the patients who underwent early redilation (42% vs. 8%, p = 0.0001). The procedural success rate (95%) and complication rate were similar in both groups. Follow-up angiography was performed in 86% of patients with an initially successful procedure. The incidence of restenosis was significantly higher in the group that underwent early redilation (56% vs. 37%, p = 0.007) and was similar in patients in this group who presented with stable (55%) or unstable (57%) angina. CONCLUSIONS: Rapidly recurring coronary stenoses have an extremely high rate of restenosis when again treated by coronary angioplasty, irrespective of the clinical presentation at the time of repeat dilation. The outcome in patients with early restenosis who have stable angina might be improved by delaying the repeat procedure.

Angioplasty, Balloon, Coronary↗

PubMed1992

Proto-oncogene expression in rabbit aorta after wall injury. First marker of the cellular process leading to restenosis after angioplasty?

In order to study the earliest phenomenons occurring in the arterial wall after balloon angioplasty, the level of expression of the proto-oncogenes, c-fos and c-myc, was studied in rabbit aorta after balloon denudation by using Northern blot analysis. Both c-fos and c-myc are rapidly and transitorily induced (maximal at 30 min and 2 h after mechanical injury for c-fos and c-myc respectively). By comparison, infusion of norepinephrine increases oncogene expression in normal non-denuded rabbit aorta after 1 h, but the combination of both mechanical and hormonal stimuli do not lead to a more important induction than balloon denudation alone.

Angioplasty, Balloon↗

PubMed1992

Prevention of coronary spasm by nicorandil: comparison with nifedipine.

The efficacy of nicorandil was compared with that of nifedipine in 13 patients with vasospastic angina enrolled in a randomized, placebo-controlled, crossover study. All patients had a coronary spasm during coronary arteriography, either spontaneously or ergometrine-induced. During two consecutive periods of 2 days, patients received active drugs or placebo in a randomized order. Each patient received single oral doses of 30 mg nicorandil, 10 mg nifedipine, and, on 2 days, a placebo. One hour after drug intake, patients underwent an ergometrine test with increasing doses of Methergin (ergometrine) (0.05, 0.10, 0.20, and 0.40 mg every 5 min). After placebo, the tests always were positive, and the ECG changes occurred at the same +/- 1 dose of ergometrine in 10 cases, showing good reproducibility. After nicorandil, the tests were negative in nine patients and positive for a higher or lower dose of ergometrine in three and one patient, respectively (p = 0.0034 vs. placebo). After nifedipine, the tests were negative in five patients and positive for a higher or the same dose of ergometrine in four and four patients, respectively (p = 0.0039 vs. placebo). Nifedipine (10 mg) and nicorandil (30 mg) were equally effective in eight patients; in the remaining five patients, nicorandil had better results (p = 0.06). Nicorandil (30 mg) prevents ergometrine-induced coronary spasm. This compound may be beneficial in patients with vasospastic angina.

Administration, Oral↗

PubMed1992

Dose-response curve of angiographically smooth human epicardial vessel segments to intracoronary injections of isosorbide dinitrate.

The coronary vasodilator properties of isosorbide dinitrate are well established but the doses generally used (1,000-2,000 micrograms) are still empirical. We studied, with the use of quantitative coronary arteriography (CAESAR System), the response of smooth vessel segments (greater than 1.85 mm diameter), preconstricted with methylergometrine (400 micrograms i.v.), to intracoronary injections of graded doses (5-100 micrograms) of isosorbide dinitrate and the effects of these injections on systemic hemodynamic parameters in 10 patients undergoing diagnostic coronary angiography. Six further patients, in whom the injections of isosorbide dinitrate were replaced by equivalent volumes of normal saline, served as controls. Relative to the diameter 5 min after injection of methylergometrine, the diameter increased by a mean +/- SD of 9 +/- 7, 26 +/- 12, 33 +/- 15, 38 +/- 14, and 39 +/- 16% after injections of 5, 15, 60, 240, and 1,000 micrograms, respectively, of isosorbide dinitrate. After a cumulative dose of 80 micrograms, subsequent doses did not cause further significant increases in diameter. Injection of saline in the control group did not alter the coronary diameter. A significant fall in systolic arterial pressure, compared to the control group, occurred at a cumulative dose of 320 micrograms. The mean arterial pressure and heart rate were unchanged. Significant coronary vasodilation occurs with intracoronary doses of isosorbide much smaller than those currently employed. Cumulative doses of 320 micrograms or more cause systemic hemodynamic changes without producing additional coronary vasodilation. During interventional cardiac procedures, where systemic hypotension is undesirable, the use of smaller doses of intracoronary isosorbide dinitrate than currently employed may be feasible and should be investigated further.

Adult↗

PubMed1992

Effect of ketanserin on proximal and distal coronary constrictor responses to intracoronary infusion of serotonin in patients with stable angina, patients with variant angina, and control patients.

BACKGROUND: Serotonin, released by aggregating platelets, may contribute to or cause myocardial ischemia by constricting epicardial vessels. Experimental studies suggest that this constriction is mediated by two distinct serotonin receptor subtypes: 5-hydroxytryptamine1-like (S1-like) and 5-hydroxytryptamine2 (S2). METHODS AND RESULTS: To determine the relative contribution of S1-like and S2 receptors to the vasoconstrictor effects of serotonin, we studied the effect of ketanserin (0.75 mg, intracoronary), a selective S2 receptor antagonist, on the constrictor response of human coronary vessels to intracoronary infusions of serotonin. In control patients (n = 7), serotonin (10(-4) mol/l) caused significant (p less than 0.05) constriction only in distal segments, which was significantly (p less than 0.05) inhibited by ketanserin. In stable angina patients (n = 8), serotonin (10(-4) mol/l) caused significant constriction in proximal (p less than 0.01) and distal (p less than 0.01) segments, which was significantly inhibited by ketanserin in proximal (p less than 0.05) but not distal (p = 0.30) segments. In patients with variant angina (n = 3), epicardial occlusion at the site of preexisting stenoses in proximal locations occurred at infused concentrations of 10(-6) (one patient) or 10(-5) (two patients) mol/l. The infusion of the same concentration of serotonin after ketanserin again caused epicardial occlusion. CONCLUSIONS: Our results suggest that functionally important S1-like receptors that mediate vasoconstriction exist in the epicardial vessels of patients with stable or variant angina. Their activation, either at hyperreactive sites in patients with variant angina or in the distal epicardial vessels of patients with chronic stable angina, may contribute to or cause myocardial ischemia when serotonin is released after the intracoronary activation of platelets.

Adult↗

PubMed1992

[Treatment of first restenosis by recurrent angioplasty. Immediate results and angiographic follow-up after 6 months].

This report summarises the authors' experience of 421 patients treated for a first restenosis by repeat conventional balloon angioplasty with a high 6 months angiographic follow-up (84%). The immediate results were significantly less than those obtained during the same period with initial angioplasty procedures (94.5% success and 0.9% complications without any deaths during the hospital period). The 39.9% recurrent restenosis rate, on the other hand, is the same as observed after a first procedure. The risk factors of a second restenosis seem to be different from those of a first restenosis. A shorter interval between the first and second angioplasty (< 3 months) was associated with a 55% risk of restenosis compared with only 36% when the interval was > 3 months. Two operative factors were associated with a high risk of recurrent restenosis: a maximum inflation pressure > 7 atm and > or = 3 balloon inflations. These results seem to be important and should be taken into consideration when deciding on the management of patients presenting with a first restenosis.

Aged↗

PubMed1992

[Coronary angioplasty of multivessel coronary diseases. Apropos of 1664 procedures. Immediate results and results following 6 months].

Between 1980 and 1990, 1,664 coronary angioplasty procedures were performed in 1,307 patients (86.6% male) with multivessel disease. The average age was 57 +/- 3 years (range 29 to 83 years). There was a previous history of infarction in 40.1% of patients and 22.4% of the procedures were performed for unstable angina. Catheter and 58.2%, 1,220 double vessel and 444 triple vessel diseases. A total of 2,509 lesions were dilated (1.5 stenoses/patient). The primary success rate was 81.9% with 3.2% of infarcts and 3.5% emergency bypass procedures and a global mortality of 2%. The factors responsible for death in the acute and hospital phases were unstable angina, age > 70 years, and ejection fraction < 35%. Complete revascularisation was achieved in 14.3% of cases: the only predictive factor for complete revascularisation on multivariate analysis was double vessel disease. A 6 months clinical and angiographic control was obtained for 83.8% of controllable procedures (965 dilatations). The restenosis rate was 47.9%. Univariate analysis of the factors of restenosis identified clinical parameters (age > 58 years, triple vessel disease, diabetes and unstable angina), parameters related to the lesion (length of stenosis > 1 cm, percentage stenosis > 80%) and to the procedure (residual stenosis > 20%): 68.4% of patients with restenosis underwent repeat angioplasty with a significantly superior primary success rate 88.7% vs 81.9% of global successes (p < 0.001). With a 82% primary success rate with few major complications, coronary angioplasty is a safe and effective therapeutic alternative. The extent of the lesions and the presence of chronic occlusion are the main limitating factors of revascularisation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

[Abnormal origin of the left circumflex coronary artery: clinical, angiographic and prognostic aspects. Apropos of 30 cases].

The object of this study of 30 patients with an anomalous origin of the left circumflex coronary artery was to define the clinical and angiographic features of this condition and to assess its influence on morbidity and survival. The 30 patients were 24 men and 6 women with ages ranging from 29 to 76 years. An anomalous origin of the left circumflex coronary artery should be suspected when two angiographic signs are present: firstly, the visualisation of a spur of opacification in the 30 degrees LAO view of left ventriculography, present in 93% or our patients; secondly, during selective left coronary angiography in the transverse view, an ascular zone is observed where the normal left circumflex artery should be. Confirmation of the diagnosis depends on opacification of the left circumflex arising from the right anterior sinus of Valsalva with a separate (37%) or common (23%) orifice with the right coronary artery or arising from a proximal segment of the right coronary artery/(40%). Five patients (17%) had a significant stenosis of the anomalous left circumflex coronary artery but this was always associated with lesions of the other coronary narrowing was observed. Of these patients, one had electrocardiographic signs of myocardial ischaemia and no other cause apart from the anomalous origin of the left circumflex to explain this ischaemia. The 30 patients were followed up for an average of 6.1 +/- 3.9 years. During this period, 1 cardiac death, 1 infarction, 5 cases of angina, 4 coronary bypass procedures, and 6 coronary angioplasties were observed. Nine patients (30%) had no cardiac event during follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

[Coronary angioplasty after thrombolytic therapy].

Two strategic choices are available after thrombolytic therapy: an aggressive strategy with the objective of restoring blood flow in the coronary artery responsible for the infarction or a conservative strategy, In the aggressive strategy, there is some debate about the timing of coronary angiography: immediate coronary angiography with a view to angioplasty during the same procedure whenever technically feasible or only when the artery remains occluded after thrombolysis ("salvage" angioplasty); or deferred coronary angiography and angioplasty with the objective of preventing recurrence of ischaemia, performed during the hospital phase before the patient's discharge. Besides this aggressive strategy, some cardiologists prefer to adopt a conservative attitude which consists in only performing coronary angiography and eventual revascularisation when the patients develop ischaemia during follow-up either spontaneously or during stress testing. Several randomised clinical trials performed in recent years, (TAMI, TIMI 2A and 2B, European Study, SWIFT), have all shown that there was no significant difference in survival or global left ventricular function between patients managed "aggressively" and those managed "conservatively". However, these studies are open to criticism, especially in the light of recent data about associated medical therapy which reduces the incidence of complications, especially of reocclusion. This point should be emphasised as secondary studies on subgroups have shown that the benefits of the aggressive strategy were totally lost in patients who developed reocclusion but, conversely, the outcome was much better if the angioplasty was followed by long-term success.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗

PubMed1992

[Nitrate derivatives and coronary vasomotricity].

The action of nitrate derivatives on the coronary arterioles is weak and very short lasting which avoids the phenomenon of a coronary steal syndrome. Investigations of the epicardial coronary vessels require vasoconstriction stress tests, usually using ergometrine, and vasodilatation tests, mainly using isosorbide dinitrate (ISDN). The combination of the two tests allows evaluation of global coronary vasomotricity which is less than 100% variation of diameter. In coronary spasm, ISDN relieves the stenosis in less than 2 minutes in nearly all cases. An infusion of ISDN also prevents most cases of arterial spasm. In effort angina, it has been possible to demonstrate paradoxal vasoconstriction during exercise due to endothelial dysfunction. The direct action of nitrate derivatives on smooth muscle which is not endothelium dependent, prevents the vasoconstriction and increases oxygen supply during exercise.

Coronary Artery Disease↗