[Results of coronary artery surgery in octogenarians]

Over an 11 year period from January 1990 to December 2000, 3282 patients underwent isolated or combined surgical myocardial revascularisation. In this group, 42 were aged 80 or over (maximum 87 years), 1.3% of the total patient population. The mean age of this subgroup was 81.8 +/- 1.75 years) with a male predominance (61.9%). All patients were autonomous and considered to be in good general and psychological health. Preoperative coronary angiography showed 33.3% of left main stem lesions either alone or associated with a right coronary lesion. The ejection fraction was over 50% in 78.6% of cases. Saphenous vein grafts were used in all but 5 patients who also had left internal mammary artery grafts. Thirteen patients (31%) underwent combined valvular surgery (11 aortic and 2 mitral valve) and 2 patients underwent combined vascular surgery. Three patients were operated as an emergency. A total of 5 patients died in the first 30 postoperative days, a hospital mortality of 11.9%. There were 2 postoperative hemiplegias and 2 cases of renal failure which were aggravated in the postoperative period. The other patients were discharged from hospital with a satisfactory cardiac and functional status. The global mortality was 14% at 3 years and 18% at 5 years. The main bad prognostic factor for survival was the association of aortic valve surgery. In selected octogenarians in good general and psychological health without severe co-morbid conditions, surgical myocardial revascularisation may be considered with an acceptable operative risk.

Cyclosporin A increases basal intracellular calcium and calcium responses to endothelin and vasopressin in human coronary myocytes

Cyclosporin A (CsA) is a widely used immunosuppressive agent with severe side effects including hypertension. Here, we investigated the effects of CsA on intracellular free calcium ([Ca(2+)](i)) and the mechanisms involved in vasoconstriction in cultured human coronary myocytes. We used the Fura-2 technique for Ca(2+) imaging. Acute application of CsA at therapeutic concentrations (0.1-10 micromol/l) had no effect. Chronic exposure to CsA (1 micromol/l) for 24 h induced a small (20 nmol/l) but highly significant increase of basal [Ca(2+)](i) and enhanced the occurrence of spontaneous Ca(2+) oscillations. Endothelin- and vasopressin-induced rises of [Ca(2+)](i) were also enhanced. The demonstration that CsA increases basal [Ca(2+)](i) in addition to its impact on agonist receptor stimulation is of major importance for new therapeutic approaches.

Autologous peripheral blood stem cell transplantation following heart transplantation for primary systemic amyloidosis

A 47 years old woman was admitted with severe congestive heart failure. Cardiac echography showed increased intra-ventricular septum thickness, and there was a serum Ig G lambda monoclonal component. Cardiac biopsies confirmed diffuse amyloidosis of Al type. To avoid cardiac toxicity of chemotherapy, the patient received first a heart transplantation (HT), followed six months later by melphalan 200 mg/m(2) and autologous peripheral blood stem cell support (PBSCT). This case suggests that such strategy is feasible with a favorable outcome, and HT may be an appropriate procedure for some patients with Al amyloidosis who meet the criteria for PBSCT.

Aspergillus flavus mitral valve endocarditis after lung abscess

A 16-year-old male with bone marrow failure due to chemotherapy for recurrent acute lymphoblastic leukemia developed an abscess in the lower lobe of the left lung draining through a bronchogastric fistula, as well as mitral valve endocarditis with large vegetations. After a course of antifungal therapy, the left lobe was removed and the fistula closed. The mitral valve was then replaced, after a failed attempt at valve repair, by a mechanical, double-leaflet prosthesis. Microscopy of the lung and heart specimens disclosed hyphae. Cultures of both specimens on Sabouraud's medium recovered a fungus, which was identified by culturing on Czapek's medium as Aspergillus flavus. Despite further antifungal therapy, fatal embolism developed. The emboli contained the same A. flavus as the valve and lung specimens. This case confirms the grim prognosis of primary Aspergillus endocarditis in immunocompromised patients, and suggests that delayed surgical treatment and the presence of another focus of Aspergillus infection may increase the risk of death.

[Is atypical sodium current related to arterial pathophysiology?]

Primary cultured human coronary myocytes, derived from patients with end-stage heart failure (NYHA, classes III and IV) caused by an ischemic disease and undergoing heart transplantation, express a voltage-gated tetrodotoxin-sensitive sodium current (INa). This current has atypical electrophysiological and pharmacological properties and regulates intracellular sodium ([Na+]i) and calcium ([Ca2+]i). Our work is aimed at identifying its role and regulation of expression during pathophysiology. We currently investigate whether INa is expressed in vascular smooth muscles cells (VSMCs) isolated from either healthy or diseased (atheromatous) arteries in human and, in parallel, in pig, rabbit and rat. Cells were enzymatically isolated, primary cultured and macroscopic INa were recorded using the whole cell patch clamp technique. We found that INa is expressed in VSMCs grown from human aortic (90%; n = 48) and pulmonary (44%; n = 16) arteries and in the human aortic cell line HAVSMC (94%; n = 27). INa was also detected in pig coronary (60%; n = 25) and rabbit aortic (47%; n = 15) VSMCs, but not in rat aortic myocytes (n = 30). These different INa were activated at similar range of potentials (approximately -45 mV), had similar sensitivity to tetrodotoxin (IC50 around 5 nM) and similar density (2 to 4 pA/pF). Their expression was related to cell dedifferentiation in vitro. However, INa was observed more frequently in human myocytes derived from diseased arteries (ischemic cardiopathy) than in those derived from healthy tissues (dilated cardiopathy). In conclusion, INa may contribute to increase the basal arterial contractility and play a role in pathological situations including hypertension.

Vertebral artery surgery with cardiopulmonary bypass and deep hypothermia

Deep hypothermia was proposed to prevent neuronal ischemia and stroke during surgical procedures on arteries that supply the brain, especially with extended occlusive lesions on both internal carotid arteries. The interest of this therapeutic option is still under discussion, even in the case of combined cardiac and cerebrovascular surgery. We report the case of a 53-year-old male who was admitted to our institution for symptomatic vertebrobasilar insufficiency. Angiography showed a thrombosis of both internal carotid arteries, stenosis of both external carotid arteries, and a tight proximal stenosis of a dominant right vertebral artery. Endarterectomy and angioplasty of the origin of the right external carotid artery was done first to increase the blood supply to the brain via collateral arteries connecting the extra- and intracranial networks. Six weeks after this, a right-sided vertebral-to-carotid artery anastomosis was performed during cardiopulmonary bypass (CPB)-induced deep hypothermia for optimal neuronal protection, with good results. However, early thrombosis of the right vertebral artery requiring reintervention in normothermia, without any stroke, indicate that deep hypothermia was unnecessary in this case, probably because of the previous natural and surgical development of collateral circulation. However, there was no means of predicting this in a reliable manner before the procedure and deep hypothermia appeared a safe technique for neuronal protection without any specific postoperative complications.

Successful conservative surgery of acute ascending aortic dissection occurring during coronary angiography

We reported the case of an acute aortic dissection complicating right guiding catheter manipulation during engagement in the right coronary ostium. Despite absence of hemodynamic deterioration, dissection progressed rapidly from the sinus of Valsalva to the ascending aorta along its entire length. At surgery, performed in emergency, the aorta was not dilated and the aortic wall did not appear pathologic. Therefore conservative surgery was performed, consisting of suture of the aortic tear and incollage of the false lumen, with good immediate and mid-term results.

Prognostic value of myocardial lactate dehydrogenase subunit ratio in heart transplant recipients

BACKGROUND

Allograft coronary artery disease (CAD) is a major long-term complication in heart transplant recipients. Unfortunately, methods for early estimation of the likelihood of development of the disease are not currently available. Lactate dehydrogenase (LDH) is composed of heart and muscle subunits. The prevalence of these subunits in LDH isoenzymes (LDH1 through LDH5) is an accurate indicator of myocardial metabolism and allows indirect estimation of oxygen availability to cardiocytes. This study investigated the prognostic value of myocardial LDH composition for the occurrence of morbid events in patients with severe allograft CAD.

METHODS

Eighty-eight heart transplant recipients were followed up for a median of 4.3 years. The isoenzymes of LDH and the ratio of the heart and muscle subunits (H/M) were determined in 526 endomyocardial biopsy samples.

RESULTS

Eleven patients (12%) died from allograft CAD during follow-up. They had significantly lower H/M ratios compared with event-free patients, with clear differences as early as 6 months after operation. A threshold value of 2.75 was derived from receiver operating characteristic curve analysis. Patients showing H/M values < or =2.75 had a significantly higher mortality rate than did those with higher values (p=.0003). Importantly, the H/M ratio emerged as the most powerful independent prognostic factor of death by allograft CAD (p=.001) in a multivariate model.

CONCLUSIONS

Poor myocardial aerobic metabolism estimated through low H/M values was highly predictive of cardiac death resulting from severe allograft CAD. Analysis of LDH isoenzyme profile in routine endomyocardial biopsies might be of clinical value.

[Extracorporeal circulation for warming in severe accidental hypothermia. 3 cases]

BACKGROUND

Severe accidental hypothermia with central temperature below 28 degrees C can result from prolonged cold exposure and lead to a fatal outcome by spontaneous or provoked ventricular fibrillation.

CASE REPORT

Three patients were referred for central temperature below 24 degrees C. At admission, the patients had major ventricular rythm disorders (two were in a state of circulatory arrest and the third had auricular fibrillation and circulatory collapse). Emergency care associated internal warning using extracorporeal circulation via the femoro-femoral route with a centrifuge pump. Outcome was favorable in 2 cases.

DISCUSSION

Prognosis is very poor in patients who experience severe accidental hypothermia (< 28 degrees C) with circulatory collapse. Death often results from major rhythm disorders. Optimal emergency rewarming and oxygenation using extracorporeal circulatory assistance can be successful.

Exercise tolerance in heart transplant patients with altered pulmonary diffusion capacity

To test whether orthotopic heart transplant (OHT) patients with low pulmonary diffusion capacity have a greater limitation to exercise than OHT patients with normal pulmonary diffusion capacity, we investigated cardiorespiratory responses and blood gases in two groups of OHT patients, one with low (LdG) and the other with normal pulmonary diffusion capacity (NdG), during a graded exercise test. The results showed 1) significantly reduced peak power (P < 0.05), peak oxygen uptake (VO2, P < 0.001), peak oxygen pulse (VO2/heart rate, P < 0.01), peak minute ventilation (VE, P < 0.05), and delta PaO2 (peak PaO2 - rest PaO2, P < 0.05) in LdG versus NdG; 2) a nonsignificant decrease in peak heart rate in LdG (P < 0.13, P = 24%); and 3) significant increases in peak respiratory equivalent for oxygen (VE/VO2, P < 0.05) and delta P(A-a)O2 (peak P(A-a)O2 - resting P(A-a)O2, P < 0.05) in LdG versus NdG. No significant difference was found for PaO2 and PaCO2 at rest or at peak exercise between the groups. A strong correlation was found between pulmonary diffusion capacity (TLCO/VA) and peak VO2 (r = 0.81, P < 0.01); that is, TLCO/VA explains 66% of the variance in peak VO2. We conclude that OHT patients with decreased pulmonary diffusion capacity have a lower exercise tolerance than patients with normal pulmonary diffusion capacity. However, because of the lack of exercise-induced hypoxemia, diffusion abnormalities are not the main limiting factor for exercise tolerance in the low diffusion group.

[Outcome of type I acute aortic dissection operated after 70 years of age. A retrospective study of operated dissection of the aorta in the over 70 years old]

The aim of this study was to assess the perioperative mortality and long-term outcome of Type I dissection of the aorta operated in patients over 70 years age. Of the 87 dissections of the aorta operated between 1988 and 1995, 19 concerned patients aged 71 to 79 (average 74.1 +/- 2.4 years). The procedure was replacement of the ascending aorta with gluing of the false lumen in call ases. Two patients also underwent aortic valve replacement and three also had replacement or repair of the aortic arch. Eleven patients (56%) had circulatory arrests lasting an average of 33 minutes (10-86 minutes). The mortality rate at 30 days was 31.5% (6/19): 3 deaths were due to bleeding, 1 to mesenteric infarction, 1 to cardiac arrhythmia and 1 to a cerebrovascular accident. The morbidity was 53%, mainly due to neurological complications, chest infection and renal failure. After an average period of 36.8 months (range: 3 to 75 months) with no patient lost to follow-up, the late mortality was 23% (3/13), giving actuarial survival rates at 1.5 and 6 years of 63%, 47.5% and 32%, respectively (including the operative mortality). Or the survivors, 9 were in NYHA Classes I-II and 1 in class III. One patient developed a hemiparesis. The authors conclude that, despite high mortality and morbidity at 30 days, long-term survival and its quality are arguments in favour of surgical management, even in elderly patients.

Mycotic aneurysm of the extracranial carotid artery: an uncommon complication of bacterial endocarditis

This report describes a case involving mycotic aneurysm of the extracranial internal carotid artery occurring as a complication of staphylococcal endocarditis in a patient with systemic lupus erythematosus. Three main points are emphasized: (1) this complication occurred in an immunodepressed patient; (2) surgical treatment consisted of aneurysmorraphy using absorbable suture; (3) the outcome was successful with a follow-up of 24 months.

Chronic left main coronary artery occlusion: a complication of radiofrequency ablation of idiopathic left ventricular tachycardia

We describe in this report the development of chronic left main coronary artery (LMCA) occlusion in a young patient 2 years after an uncomplicated, successful ablation of idiopathic left ventricular tachycardia. This complication appears to be a late consequence of trauma to the LMCA during the procedure rather than an acute or subacute embolic event.

A novel tetrodotoxin-sensitive Na+ current in cultured human coronary myocytes

Voltage-gated Na+ currents (INaS) are usually not found in arterial smooth muscle. We enzymatically isolated myocytes from the media of left coronary arteries of heart transplant patients with ischemic cardiopathy. Using the whole-cell voltage-clamp technique (20 degrees C to 22 degrees C), we detected no INa in any of the freshly isolated myocytes. In contrast, when the cells were grown in culture, we could record a large INa. This INa was characterized by a biexponential decay comprising a fast inactivating and sustained components that could not be separated by their electrophysiological and pharmacological properties. INa activated at depolarizations positive to -50 mV, was maximal at 0 mV, and was available from relatively low resting membrane potentials (half-inactivation at -46 mV). INa was modulated by several ligands known to bind selectively at different sites of Na+ channels. It was blocked with high affinity by tetrodotoxin (IC50, approximately 10 nmol/L) and local anesthetics (bupivacaine and lidocaine; IC50, approximately 100 nmol/L) and by Cd2+ (IC50, approximately 300 mumol/L). INa was modulated by Na+ channel agonists such as toxin AsV from Anemonia sulcata and veratridine, which slowed current kinetics dramatically. In conclusion, human coronary myocytes in culture can express an atypical tetrodotoxin-sensitive INa with a large sustained component, which is expected to contribute to massive Na+ influx into these cells. Phenotypic modulation of the expression of this INa may be related to cell dedifferentiation and proliferation.

Voltage-gated calcium channel currents in human coronary myocytes. Regulation by cyclic GMP and nitric oxide

Voltage-gated Ca2+ channels contribute to the maintenance of contractile tone in vascular myocytes and are potential targets for vasodilating agents. There is no information available about their nature and regulation in human coronary arteries. We used the whole-cell voltage-clamp technique to characterize Ca2+-channel currents immediately after enzymatic dissociation and after primary culture of coronary myocytes taken from heart transplant patients. We recorded a dihydropyridine-sensitive L-type current in both freshly isolated and primary cultured cells. A T-type current was recorded only in culture. The L- (but not the T-) type current was inhibited by permeable analogues of cGMP in a dose-dependent manner. This effect was mimicked by the nitric oxide-generating agents S-nitroso-N-acetylpenicillamine (SNAP) and 3-morpholinosydnonimine which increased intracellular cGMP. Methylene blue, known to inhibit guanylate cyclase, antagonized the effect of SNAP. Inhibitions by SNAP and cGMP were not additive and seemed to occur through a common pathway. We conclude that (a) L-type Ca2+ channels are the major pathway for voltage-gated Ca2+ entry in human coronary myocytes; (b) their inhibition by agents stimulating nitric oxide and/or intracellular cGMP production is expected to contribute to vasorelaxation and may be involved in the therapeutic effect of nitrovasodilators; and (c) the expression of T-type Ca2+ channels in culture may be triggered by cell proliferation.

Involvement of endothelin in mononuclear phagocyte inflammation in asthma

BACKGROUND AND AIM

Endothelin has bronchoconstrictive, vasoactive, and inflammatory properties and may be involved in the pathogenesis of asthma. We have studied the involvement of endothelin in asthma by examining its expression and release by mononuclear phagocytes obtained from 56 patients with asthma and 32 control subjects and the activation of mononuclear phagocytes by endothelin.

METHODS

Endothelin immunoreactivity was studied by using immunocytochemistry on monocytes and alveolar macrophages. Spontaneous and lipopolysaccharide-induced endothelin release from monocytes and alveolar macrophages was studied by radioimmunoassay. The proportion of intracellular endothelin was assessed after cell disruption by Triton (Union Carbide Corp., Bound Brook, N.J.). The release of fibronectin and tumor necrosis factor-alpha induced by endothelin was studied in alveolar macrophages by enzyme immunoassay.

RESULTS

Endothelin immunoreactivity was significantly increased in cells from patients with asthma in comparison with those from the control group, but its release by alveolar macrophages was similar in both groups. Levels in the cell lysates and supernatants were similar for patients with asthma and normal subjects. Endothelin significantly increased the release of tumor necrosis factor-alpha and fibronectin by alveolar macrophages from normal subjects and patients with stable asthma, but it significantly decreased their release in patients with unstable asthma.

CONCLUSION

This study suggests a role for endothelin in airway inflammation in asthma. Endothelin may act in a different fashion on alveolar macrophages, depending on the degree of stability of the disease.

Influence of post-surgery time after cardiac transplantation on exercise responses

Influence of post-surgery time after cardiac transplantation on exercise responses. Med. Sci. Sports Exerc., Vol. 28, No. 2, pp. 171-175, 1996. To test the hypothesis that exercise response changes with time after cardiac transplantation, we investigated the cardiorespiratory responses of nine orthotopic heart transplant patients (52.4 +/- 2 yr) during graded exercise tests (30 W.3 min-1) done at 1, 3, 6, 9 and 12 months post-surgery. At peak exercise, 1) oxygen uptake per kg of body weight (VO2), minute ventilation (VE) and oxygen pulse (O2 pulse) did not change significantly between 1 and 12 months postsurgery; 2) transplanted heart rate (HRt) and delta heart rate (peak exercise heart rate--resting heart rate) increased significantly over time (P < 0.01; P < 0.05) with a marked increase between 1 and 3 months (P < 0.05); and (3) a significant negative correlation existed between O2 pulse and HRt (r = -0.36, P < 0.05), whereas no correlation was found between delta heart rate and delta VO2 (peak exercise VO2- resting VO2, l.min-1). During submaximal exercise, HRt increased significantly over time (P < 0.001); VO2, VE, and O2 pulse showed no significant change; and the VO2-HRt relationship shifted toward higher values of HRt. We conclude that, in the absence of formal physical training, the exercise response of denervated transplanted heart increases in relation to post-surgery time but does not affect oxygen uptake at submaximal and peak levels of exercise.

High frequency-induced upregulation of human cardiac calcium currents

BACKGROUND

In mammalian heart cells, Ca2+ influx through voltage-gated L-type Ca2+ channels can be upregulated by high rates of stimulation. We have investigated this important adaptive regulation in human cardiomyocytes.

METHODS AND RESULTS

Using the whole-cell patch-clamp technique, we found a high frequency-induced upregulation (HFIUR) of the dihydropyridine-sensitive L-type Ca2+ current (ICa) in human cardiomyocytes. ICa was potentiated in a graded manner with increasing rates of stimulation between 0.3 and 5 Hz. Both moderate increase of ICa peak amplitude and marked slowing of current decay contributed to large increases of Ca2+ influx (up to 80%). The maximal potentiation of ICa was reached rapidly after the change in the rate of stimulation (no more than a few seconds). Beta-Adrenergic stimulation of the cells by isoproterenol (1 micromol/L), which is well known to induce a slow (approximately 1 minute) cAMP-mediated potentiation of ICa, could enhance (when present) or promote (when absent) the HFIUR of ICa. As a consequence, the increasing effect of isoproterenol on Ca2+ influx through Ca2+ channels was dependent on the rate of stimulation. HFIUR of ICa was altered in patients with ejection fraction lower than 40% and in patients pretreated with Ca2+ antagonists or beta-blockers.

CONCLUSIONS

Upregulation of Ca2+ entry through voltage-gated Ca2+ channels by high rates of beating may be involved in the frequency-dependent regulation of contractility (Bowditch "staircase") of the human heart. This process, which is highly sensitive to beta-adrenergic stimulation, may be crucial in adaptation to exercise and stress.

Myocardial lactate dehydrogenase subunit ratio in cardiac allograft recipients

BACKGROUND

Allograft coronary artery disease (CAD) is a major long-term complication in heart transplanted patients. However, the metabolic basis of allograft CAD remains to be fully elucidated. We analyzed the lactate dehydrogenase heart (H) and muscle (M) isoenzyme pattern in endomyocardial biopsy specimens and the evolution of the H/M ratio to test whether changes in this ratio could be the earliest manifestation of allograft CAD.

METHODS

Twenty-four heart transplant recipients were followed up for 12 months. Endomyocardial biopsy was performed at 1, 2, 3, 6, and 12 months after transplantation. Lactate dehydrogenase 1 through 5 isoenzymes were separated by electrophoresis, and the H/M ratio was calculated. Two groups of patients were identified: group 1 (n = 20), patients without allograft CAD; and group 2 (n = 4), patients with poor outcome (three deaths, 1 case of low cardiac output) and angiographic and histologic evidence of allograft CAD.

RESULTS

Both groups had similar H/M baseline values. The H/M ratio was higher (p = 0.01) in group 1 at 6 months (3.48 +/- 0.64 versus 2.17 +/- 0.43) and 12 months (3.76 +/- 0.92 versus 2.18 +/- 0.45) when compared with group 2. The H/M ratio increased from 2.78 +/- 0.89 at 1 month to 3.76 +/- 0.92 at 12 months (p = 0.02) in group 1 and decreased in group 2 (2.86 +/- 0.49 versus 2.18 +/- 0.45; not significant).

CONCLUSIONS

Changes in H/M ratio reflect an anaerobic shift in the lactate dehydrogenase isoenzyme composition and can be taken as an early indicator of allograft CAD.