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Biomedical subjects

J M Lablanche

Publications and source records attributed to J M Lablanche.

At least 55 records · Page 3Linked to original sources
PubMed1994

Long-term oral administration of L-arginine reduces intimal thickening and enhances neoendothelium-dependent acetylcholine-induced relaxation after arterial injury.

BACKGROUND: Nitric oxide (NO), in addition to its potent vasorelaxant properties, may participate in growth regulation of cultured smooth muscle cells. It was recently demonstrated that in vivo endothelial injury induces the production of NO from L-arginine in the arterial wall. METHODS AND RESULTS: We studied the effects of long-term administration of L-arginine, the precursor of NO, on neointimal thickening and on neoendothelium-dependent vasorelaxation 4 weeks after balloon denudation of normocholesterolemic rabbit iliac arteries. Rabbits were fed with either a standard diet or a diet supplemented with L-arginine (2.25%) in their drinking water 3 days before and during 4 weeks after balloon denudation. The effectiveness of L-arginine supplementation was confirmed by measurement of plasma arginine levels. L-Arginine had no effect on hemodynamic parameters. All animals were killed 4 weeks after balloon denudation, and a digital histomorphometric analysis of three serial nonconsecutive histological cross sections per iliac artery was performed. Intimal thickening was reduced (P < .05) from 0.43 +/- 0.08 (SE) mm2 in controls (n = 8) to 0.24 +/- 0.02 mm2 in treated animals (n = 8). Ten animals (n = 5 in each group) were used for in vitro vasoreactivity assessment 4 weeks after balloon denudation. Neoendothelium-dependent acetylcholine-induced relaxation (10(-8) mol/L to 3.10(-5) mol/L) in treated animals (Emax = -24.1 +/- 5.5%) was significantly greater than in controls (Emax = -8.9 +/- 2.2%). Endothelium-independent relaxation did not differ between groups (Emax = -58.1 +/- 6.5% in L-arginine-supplemented animals versus -52.9 +/- 6.8% in controls). CONCLUSIONS: Our results demonstrate that L-arginine, a precursor of NO, reduces neointimal thickening after balloon denudation and improves neoendothelial-dependent acetylcholine-induced relaxation.

Acetylcholine↗
PubMed1994

[Predictive factors of primary success after coronary angioplasty. Qualitative and quantitative angiography of 3679 coronary stenosis before and after dilatation].

This study summarises the authors' experience of the prediction of primary success of coronary balloon angioplasty. A qualitative and quantitative angiographic study of 3679 coronary stenoses was undertaken before and after dilatation. Total occlusions before angioplasty and dilatations of saphenous vein bypass grafts were excluded. Two parameters were noteworthy: the occurrence of acute occlusion of the lesion during or immediately after angioplasty and the degree of residual stenosis as assessed by quantitative angiography. After multivariate analysis, 3 factors seemed strongly predictive of the risk of acute occlusion: the percentage stenosis before angioplasty, a left coronary artery stenosis and stenosis situated at the point of angulation of an artery. Quantitative angiographic studies identified 4 factors predictive of significant residual stenosis: the percentage stenosis before angioplasty, the irregularity of the contours of the lesion stenosis situated at the point of angulation of an artery and the presence of calcification. This study therefore shows at least two important discordances with the ACC/AHA morphological classification of coronary stenosis: firstly, excentricity would not seem to be a risk factor for primary failure of angioplasty and, secondly, excluding total occlusions, the percentage coronary stenosis before angioplasty as assessed by quantitative coronary angiography would seem to be the main predictive factor of both the risk of occlusion and the degree of residual stenosis.

Aged↗
PubMed1994

[Electron microscopic comparison of the antithrombotic potential of 2 low osmolality iodine contrast media in percutaneous transluminal coronary angioplasty].

The antithrombogenic potentials of two low osmolality iodine contrast media, ioxaglate (Iox), an ionic product, and iopamidol (Iop), a non-ionic product, were compared in a multicentre, randomised, double-blind study in 64 patients undergoing percutaneous transluminal coronary angioplasty (PTCA) by scanning electron microscopy for the presence of thrombotic material on the guiding catheter (GC) and guide wires (GW). The procedure was strictly standardised: stable angina, type A coronary lesions; aspirin administration (at least 300 mg the day before and on the day of angioplasty); heparinisation (10000 IU at the beginning of the procedure); same GCs (Marathon Baxter 8F), same GWs (Veriflex USCI 0.014). The tips of the catheters and guide wires were scanned by an electronic microscope in a double-blind protocol. The scores for the number of erythrocytes (RBCs), platelets (PLs) and constituted thrombi (THi) were; thickness scored from 0 to 3, the % surface covered and an index of volume combining these two parameters. The clinical and angiographic characteristics of the 2 groups were strictly comparable. The time that the GCs and GWs were in the circulation were 30.0 +/- 2.3 vs 32.6 +/- 3.0 minutes for the former, and 18.6 +/- 1.8 vs 17.1 +/- 1.4 minutes for the later in the Iox and Iop groups, respectively (NS). An angiographic filling defect was not observed in any of the patients in the Iox group and in 4 patients (13%) in the Iop group (NS). The number of thrombotic elements observed on the GCs (RBCs, PLs, THi) was negligible in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1993

Usefulness of quantitative and qualitative angiographic lesion morphology, and clinical characteristics in predicting major adverse cardiac events during and after native coronary balloon angioplasty. CARPORT and MERCATOR Study Groups.

Major, adverse cardiac events (death, myocardial infarction, bypass surgery and reintervention) occur in 4 to 7% of all patients undergoing coronary balloon angioplasty. Prospectively collected clinical data, and angiographic quantitative and qualitative lesion morphologic assessment and procedural factors were examined to determine whether the occurrence of these events could be predicted. Of 1,442 patients undergoing balloon angioplasty for native primary coronary disease in 2 European multicenter trials, 69 had major, adverse cardiac procedural or in-hospital complications after > or = 1 balloon inflation and were randomly matched with patients who completed an uncomplicated in-hospital course after successful angioplasty. No quantitative angiographic variable was associated with major adverse cardiac events in univariate and multivariate analyses. Univariate analysis showed that major adverse cardiac events were associated with the following preprocedural variables: (1) unstable angina (odds ratio [OR] 3.11; p < 0.0001), (2) type C lesion (OR 2.53; p < 0.004), (3) lesion location at a bend > 45 degrees (OR 2.34; p < 0.004), and (4) stenosis located in the middle segment of the artery dilated (OR 1.88; p < 0.03); and with the following postprocedural variable: angiographically visible dissection (OR 5.39; p < 0.0001). Multivariate logistic analysis was performed to identify variables independently correlated with the occurrence of major adverse cardiac events. The preprocedural multivariate model entered unstable angina (OR 3.77; p < 0.0003), lesions located at a bend > 45 degrees (OR 2.87; p < 0.0005), and stenosis located in the middle portion of the artery dilated (OR 1.95; p < 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1993

Discordant results of visual and quantitative estimates of stenosis severity before and after coronary angioplasty.

The ability to accurately estimate the severity of epicardial coronary stenoses is critical in the assessment of the immediate and long-term results of percutaneous transluminal coronary angioplasty (PTCA). We prospectively compared visual estimates, performed by experienced interventional cardiologists, with computerized quantitative angiographic measurements of stenosis severity in a group of patients (n = 305) before, immediately after and 6 months after PTCA. Before PTCA the visual estimate of the mean (+/- SD) percentage stenosis severity, 80.6 (+/- 9.7)%, was significantly (P < 0.001) higher than the equivalent value, 73.4 (+/- 11.1)%, obtained with use of quantitative angiography. Immediately after PTCA the visual estimate of the mean residual stenosis, 18.8 (+/- 12.3)%, was significantly (P < 0.0001) lower than the equivalent quantitative estimate, 37.4 (+/- 14)%. Additionally, the residual stenosis was more frequently (18% vs. 3%) classified as significant (> 50%) by quantitative angiography. At follow-up, quantitative measurements of stenosis severity showed a Gaussian distribution with a mean of 54.8 (+/- 21)%, whereas visual estimates had a bimodal distribution with populations greater than 70% and less than 50%. Visual estimates provide an inaccurate assessment of the immediate and medium term results of PTCA. Quantitative measurements suggest that the immediate results of PTCA are frequently misclassified as successful by the operator. Conversely, restenosis rates are underestimated by the operators suggesting that a more objective method must be used in trials to assess the impact of new therapies on the rate of restenosis.

Angioplasty, Balloon, Coronary↗
PubMed1993

Cardioprotective effect of intracoronary nifedipine during percutaneous transluminal coronary angioplasty. A French double-blind cross-over multicentre study.

The aim of this double-blind, placebo-controlled, cross-over study was to assess the cardioprotective effect of intracoronary nifedipine during percutaneous transluminal coronary angioplasty balloon occlusion. A balloon inflation without drug injection was initially made to ascertain that a shift of the ST segment (> or = 2 mm, 0.08 s after the J point) appeared (inclusion criterion). Two other balloon inflations were preceded by intracoronary injection of either 0.2 mg nifedipine or placebo, distal to the stenosis through the balloon catheter. The evaluation criteria were (1) time to ST segment shift, and (2) maximal amplitude of ST segment shift caused by balloon occlusion. Comparison of the data used an analysis of variance. Sixty-seven patients (mean age 54 +/- 8 years; 54 male, 13 female) were studied; 50 patients had 1-, 16 patients 2- and 1 patient 3-vessel disease. The dilated vessel was the left anterior descending coronary artery (n = 51), the right coronary artery (n = 12) and the left circumflex coronary artery (n = 4). Balloon inflation time was 100 +/- 31 s in the nifedipine group and 93 +/- 29 s in the placebo group. Five patients were excluded (procedure stopped after the first inflation in 1 and ST segment shift < 2 mm during the first inflation in 4). The time to 2-mm ST segment shift was longer in the nifedipine group than in the placebo group (62 +/- 40 s versus 51 +/- 40 s, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Heparin does not inhibit oncogene induction in rabbit aorta following balloon denudation.

OBJECTIVE: Smooth muscle cell proliferation and migration are the predominant responses to intimal and medial injury after percutaneous transluminal coronary angioplasty. The in vivo inhibitory effect of heparin on these responses is well documented. To test the hypothesis that the antiproliferative effect of heparin in vivo may be related to an inhibition of proto-oncogene expression, the effects of pretreatment with heparin on the expression of the c-myc, c-fos and c-jun proto-oncogenes were examined in a rabbit model of balloon denudation. METHODS: Animals were randomised 5 h before balloon denudation to receive a subcutaneous injection of unfractionated heparin (7500 IU.kg-1, n = 7) or saline (n = 6). Total RNA extracted from the aorta 1 h after balloon denudation was analysed by northern blot technique. A histological study was also performed in saline treated (n = 4) and heparin treated (n = 4) animals 28 d after balloon denudation. RESULTS: The histological study showed that the degree of neointimal thickening was significantly less in heparin treated animals. However, the level of expression of the proto-oncogenes we studied was similar in both groups. CONCLUSIONS: Heparin inhibits neointimal thickening after balloon denudation. This inhibition is not associated with an overall decrease in the level of expression of the c-myc, c-fos, or c-jun proto-oncogenes in the arterial wall, suggesting that the antiproliferative effect of heparin may be due to an effect on other events in the cell cycle.

Animals↗
PubMed1993

Prognostic significance of silent myocardial ischaemia during maximal exercise testing after a first acute myocardial infarction.

Clinical, exercise, and angiographic variables, and long-term follow-up were compared in patients, who, during maximal Bruce exercise testing after a first acute myocardial infarction (AMI), had positive responses to exercise testing (n = 116, 38% of 303) with (n = 23, group I) or without (n = 93, group II) angina. Group I patients more often (52 vs 19%, P < 0.001) had a history of pre-infarction angina. Group II had a greater proportion (75 vs 52%, P < 0.05) of inferior wall AMI, whereas group I had a greater proportion (30 vs 19%, P < 0.01) of non-Q wave AMI. Total exercise duration was significantly (P < 0.01) longer in group II (7.6 +/- 3.2 vs 5.5 +/- 3.1 min). Maximal exercise heart rate (144 +/- 22 vs 133 +/- 21, beats.min-1 P < 0.05) was also higher in group II. A greater proportion of group II patients (37 vs 9%, P < 0.05) had single-vessel disease, whereas multivessel disease was more common (91 vs 63%, P < 0.03) in group I. Left ventricular function was similar in both groups. During follow-up (48 +/- 22 months) the incidence of cardiac death (group I, 3.3%, group II, 4.8%), of recurrent infarction (group I, 4.8%, group II 3.3%), and of revascularization procedures (group I, 28.5%, group II, 19.8%) were similar in both groups. Although asymptomatic exercise-induced ischaemia was associated with better exercise performance and less extensive coronary disease than symptomatic ischaemia, it had the same long-term prognostic implications.

Adult↗
PubMed1993

Repeat percutaneous coronary angioplasty; clinical and angiographic follow-up in patients with stable or unstable angina pectoris.

This study analyses the immediate outcome and the risk of recurrent restenosis in patients who, at the time of repeat coronary angioplasty for a first restenosis, had unstable (n = 50), 19%) or stable (n = 218, 81%) angina. Successful angioplasty was accomplished in 250 (93%) patients, 222 (89%) of whom had follow-up angiography. Mean time from initial to repeat angioplasty was shorter (P = 0.0002) and angiographic evidence of thrombus was commoner (P = 0.0001) in the unstable group. Major complications (coronary artery bypass grafting or myocardial infarction) were more frequent (P < 0.01) in the unstable group (6% vs 0.5%); no procedure-related deaths occurred. The angiographic rate of restenosis was significantly higher in the unstable group (61% vs 43%, P < 0.05). Despite this high rate of recurrent restenosis, most of the patients in both groups were either asymptomatic or had atypical chest pain at follow-up. Repeat coronary angioplasty, in patients with unstable angina, has a high primary success rate but a higher risk of acute complications than in patients with stable angina. The angiographic rate of restenosis was significantly higher in unstable than in stable patients; however, the clinical status of most patients was improved at follow-up.

Aged↗
PubMed1993

Potassium channel activators in vasospastic angina.

Activation of potassium channels induces relaxation of vascular smooth muscle, and experimental studies have demonstrated that potassium channel activators have potent coronary vasodilator properties. In humans, nicorandil, a potassium channel blocker, causes vasodilatation not only in angiographically normal segments but also at sites of dynamic coronary stenosis, where coronary spasm has been provoked by methylergometrine as well as at sites of spontaneous spasm. The efficacy of nicorandil in relieving ergometrine-induced spasm is comparable to that of nifedipine. Oral administration of nicorandil significantly reduces the frequency of anginal episodes in patients with vasospastic angina, and either as monotherapy, or in conjunction with other agents is a novel therapeutic option in patients with vasospastic angina.

Angina Pectoris, Variant↗
PubMed1993

Relative prognostic value of clinical, exercise, and angiographic data after a first myocardial infarction.

BACKGROUND: Studies examining the relative value of clinical, exercise test, and angiographic data in the prediction of further clinical events after a first acute myocardial infarction (AMI) have produced conflicting results. METHODS: We examined the relative value of clinical, exercise test, and angiographic data as predictors of death, recurrent infarction, and the subsequent development of angina or dyspnea in 303 consecutive patients who underwent exercise testing and coronary angiography within 2 months of an uncomplicated first acute myocardial infarction (AMI), and who were followed for 48 (+/- 22) months. RESULTS: A combination of two clinical and two exercise variables correctly identified 79% of subsequent deaths. No variables had a predictive value for re-infarction. A combination of two exercise variables correctly identified 75% of patients who developed angina during follow up. A combination of two clinical variables and one exercise variable correctly identified 76% of patients who developed dyspnea during follow up. CONCLUSIONS: Exercise testing provided useful prognostic information independent of clinical data. Combining clinical and exercise data identified a group of patients at low risk of future events. In this low-risk group of patients, the addition of angiographic data did not provide additional prognostic information.

Adult↗
PubMed1993

Restenosis rate after multiple percutaneous transluminal coronary angioplasty procedures at the same site. A quantitative angiographic study in consecutive patients undergoing a third angioplasty procedure for a second restenosis.

BACKGROUND: Several studies suggest that repeated percutaneous transluminal coronary angioplasty procedures at the same site are associated with a progressively increasing risk of further restenosis and that short time intervals between successive procedures are predictive of future restenosis. METHODS AND RESULTS: We assessed by quantitative coronary angiography the angiographic probability of restenosis when repeat percutaneous transluminal coronary angioplasty was performed at a site where restenosis had occurred after two previous angioplasty procedures. Of 99 consecutive patients who underwent a third angioplasty procedure, 96 had successful procedures. Uncomplicated failure (residual stenosis > or = 50%) occurred in 3 patients. No major complications occurred. Follow-up angiography was routinely advised; it was performed in 83 patients (86%) with successful procedures. Restenosis (recurrence of > or = 50% stenosis determined by quantitative coronary angiography) occurred in 32 patients (39%). An interval of < 3 months between the second and third angioplasty was strongly associated (P < .005) with the occurrence of further restenosis after a third procedure. CONCLUSIONS: The angiographic probability of further restenosis after three successive angioplasty procedures at the same site is similar to that reported after a first angioplasty procedure in studies that used a similar definition of restenosis. Patients who undergo a third angioplasty procedure within 3 months of a previous procedure at the same site have a much higher risk of subsequent restenosis. This easily identified subgroup may benefit from an alternative therapeutic approach.

Angioplasty, Balloon, Coronary↗
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↗