Biomedical subjects

E Aptecar

Publications and source records attributed to E Aptecar.

46 records · Page 3Linked to original sources

PubMed1992

[Can solid state Holter monitoring replace endomyocardial biopsy in patients with heart transplantation?].

Acute cardiac graft rejection after transplantation, the diagnosis of which is based on the findings of endomyocardial biopsy, is associated with a reduction in coronary reserve due to abnormalities of the microcirculation. But this reduction in coronary reserve cause silent myocardial ischaemia (SMI)? In order to assess the frequency of SMI and ventricular arrhythmias during rejection, 53 consecutive Holter recordings were performed in 32 patients (28 men, 4 women, average age 47 +/- 11 years) 11 months after transplantation and within 24 hours of endomyocardial biopsy. The recorder which was used (Monitor One TC) analysed the ST segment in 2 leads in real time: ST segment depression of more than 1 mm lasting over 40 ms, 0.08 s after the J point were considered to be diagnostic of myocardial ischaemia. Although the frequency of SMI is low and not specific for cardiac rejection, its duration was twice as long (80 mn vs 38 mn) in this condition. On the other hand, ventricular arrhythmias are common in cardiac rejection and correlated with its severity according to Billingham's classification (VES p = 0.045; doublets p = 0.035; non-sustained VT p = 0.006).

Adolescent↗

PubMed1992

[Primary isolated dissection of the left anterior descending coronary artery].

The authors report the case of a 30 year old Senegalese man admitted with an acute antero-septo-apical myocardial infarction which was fibrinolysed at the 5th hour. Coronary angiography showed dissection of the left anterior descending artery. This young patient with no previous medical history or cardiovascular risk factors had an abnormal skin biopsy showing proliferation of the elastic tissues. Eight months after the infarct the patient is asymptomatic and the appearances of dissection have disappeared. This case is original because the dissection occurred in a man, affecting the left anterior descending artery, with a good outcome after fibrinolysis (4th case), the angiographic regression of the arterial lesion and the possible pathogenetic mechanism of disease of elastic tissues.

Adult↗

PubMed1991

Results and follow-up after percutaneous pulsed laser-assisted balloon angioplasty guided by spectroscopy.

BACKGROUND: Few data are available on the long-term outcome of patients who undergo laser-assisted balloon angioplasty for recanalization of occluded peripheral arteries. Because the cost of laser angioplasty is high, the value of the method should be carefully analyzed before it can be considered a routine method for recanalization. The purpose of this study was to evaluate the early and late results of laser-assisted balloon angioplasty in patients who could not be recanalized by conventional techniques. METHODS AND RESULTS: Laser angioplasty was performed in 66 patients with total occlusion of the iliofemoral artery in whom mechanical techniques failed to recanalize the obstructed vessel. The system consisted of a pulsed dye laser operated at 480 nm, 2 microseconds/pulse, 5 Hz, 50 mJ/pulse coupled into a 0.021-in. laser catheter. The treatment laser was connected with a diagnostic laser to induce tissue fluorescence for spectroscopic analysis via the same fiber. The treatment laser was emitted only when atheromatous tissue was recognized. After a pilot hole was created by laser emission, dilatation was performed to enlarge the channel. The mean length of occlusion was 8.8 +/- 6.1 cm. The primary success rate was 82%. It did not depend on the length of occlusion but was greater in non-calcified than in calcified lesions (88% versus 71%, p less than 0.03). Complications included seven early reocclusions that could be recanalized and eight perforations without clinical sequelae. At a mean 18-month follow-up, 64% of the laser-treated arteries remained patent. The rate of patency was related neither to the length of the occlusion nor to calcifications but was lower in patients who had early reocclusion (p less than 0.02). CONCLUSIONS: Pulsed dye laser-assisted balloon angioplasty is effective for recanalization of totally occluded arteries that cannot be treated by conventional means. The efficacy is limited by calcifications. The long-term patency rate is acceptable given the severity of the lesions.

Angioplasty, Laser↗

PubMed1991

[Results of pulsed laser angioplasty of peripheral arteries guided by spectroscopy].

Seventy-six patients with complete occlusion of the iliac, femoropopliteal or distal arteries underwent laser angioplasty after failure of attempted mechanical recanalization by conventional angioplasty. The energy source was a dye pulsed laser emitting at 480 nm, 2 microseconds, 35 to 50 mJ/pulse and 5 Hz. The laser was coupled with an optical fiber of 200 microns diameter covered by a metallic spring. In order to center the laser in the arterial lumen, the fibre optic was introduced with a balloon catheter or a modified Van Andel catheter with a tapered and curved distal end with controlled torsion to direct the laser towards the lesion to be treated. The therapeutic laser was connected to a diagnostic Helium-Cadmium laser emitting at 325 nm, 50 ms and 5 mW, for the induction of tissue fluorescence analysed by a multichannel detector, itself connected to a computer programmed to differentiate atheromatous from normal tissues. The therapeutic laser was only activated when atheromatous tissue was in contact with the distal tip of the fiber optic. After vaporizing a narrow pilot channel conventional balloon angioplasty was performed. The immediate success rate was 83%; it was higher in iliac than in femoral arteries. This was less dependent on the length of occlusion than on the presence of calcification which was a common cause of failure. The complications were immediate reocclusion, perforation due to the sharp tip of the fibre and dissections without major clinical consequences. After 18 months, 64% of the arteries remained patent.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

[Coronary disease in patient following heart transplantation].

Coronary artery disease is a common and particularly severe complication of cardiac transplantation because it may cause progressive destruction of the graft by acute or chronic ischemia. The ischemia is usually silent because of cardiac denervation. Cardiac failure related to graft dysfunction, asymptomatic infarction on the ECG, or sudden death, are sometimes the only signs of severe coronary disease. The prevalence of coronary lesions has been evaluated by coronary angiography at nearly 25% at 2 years and 50% at 5 years. The distribution and morphology of the lesions are characteristic: diffuse concentric, irregular and occlusive, predominantly distal stenoses, without a distal and usually without a collateral circulation. The histological features are variable: the association of medial necrosis, severe endothelial lesions and intense parietal inflammation are suggestive of acute arteriolitis, often present during acute rejection, may be related to a common pathological process. Diffuse obliterative arteriolar lesions with concentric proliferation of medial smooth muscle are the usual appearances in transplant patients who have died or been retransplanted. There is no non-invasive diagnostic method sufficiently sensitive of specific which justifies the practice of many groups of systematic annual coronary angiography in transplanted patients. The pathogenesis is poorly understood and probably multifactorial: disorders of lipid metabolism, immunological factors, the atherogenic role of Cytomegalovirus infection. The absence of an identifiable risk factor makes preventive measures difficult. The evolutive risk justifies retransplantation in selected patients, the results of which are less satisfactory but which reduces the risk of acute coronary events and sudden death.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Angiography↗

PubMed1989

Maximal coronary vasodilator capacity of orthotopic heart transplants in patients with and without rejection.

In cardiac allograft rejection, histopathologic changes suggesting that myocardial ischemia is a component of the rejection process have been documented. To further define the coronary vascular reactivity of human heart transplant, coronary sinus blood flow and coronary resistance were measured before and after intravenous dipyridamole within the first year after transplantation in 8 patients without rejection (group II) and in 5 patients with rejection (group III). All had normal coronary arteriograms. Results were compared to those of 8 control subjects (group I). After dipyridamole, coronary sinus blood flow was increased in groups I, II and III by 303, 212 (p less than 0.01 vs group I) and 45%, respectively (p less than 0.001 vs groups I and II). Coronary resistance was reduced by 77, 73 (not significant vs group I) and 36%, respectively (p less than 0.001 vs groups I and II). Concomitantly, coronary sinus blood oxygen content was increased by 172, 145 (not significant vs group I) and 78%, respectively (p less than 0.001 vs group I, not significant vs group II). Thus, the coronary flow reserve evaluated by the dipyridamole/basal coronary sinus blood flow ratio and the coronary resistance reserve evaluated by the basal/dipyridamole coronary resistance ratio were dramatically impaired in group III (1.56 +/- 0.09 and 1.63 +/- 0.30, respectively, p less than 0.001 vs groups I and II). In contrast, they were almost normal in group II (3.11 +/- 0.42 vs 4.03 +/- 0.52 in group I, p less than 0.02, and 3.83 +/- 0.78 vs 4.45 +/- 0.81 in group I, difference not significant). Thus, the impairment of coronary reserve during heart rejection should be linked to abnormalities of the coronary microvaculature. This emphasizes the important involvement of the coronary circulation in the rejection process.

Adult↗

PubMedDate not supplied

Feasibility, safety, cost-effectiveness and 1 year follow-up of coronary stenting without predilation: a matched comparison with the standard approach.

BACKGROUND: We evaluated the feasibility, safety, procedural cost-effectiveness, radiation dose and time and 1-year target vessel revascularization rate of direct unprotected mounted stenting without previous balloon dilatation (DS) in native coronary artery lesions. METHODS: DS was attempted in 119 patients; 39 had a recent myocardial infarction, 62 had unstable angina, and 18 had stable angina. The clinical follow-up was obtained at 14+/-5 months (range 6 to 24 months). These results were compared with those for a consecutive group of 160 patients matched for type and length of lesions and who had a stent only if the post-balloon residual stenosis was >30%. RESULTS: The feasibility of DS was 112/119 (94%). The number of inflations, the length of the stent/length of the lesion ratio, the time and the dose of radiation were dramatically lower in the DS group (P<0.001). DS conferred a slight reduction in procedure-related cost [$820+/-157 for DS vs. 894+/-427 for standard dilatation (SD) per patient]. The 1-year target vessel revascularization rate was similar in both groups [nine (8%) for DS vs. 17 (11%) patients for SD, ns]. CONCLUSIONS: DS is feasible and safe in selected coronary lesions. This method provides a low rate of repeat revascularization and reduces the time and the dose of radiation compared with the standard approach.

Aged↗

PubMedDate not supplied

Abnormal coronary flow velocity reserve after coronary artery stenting in patients: role of relative coronary reserve to assess potential mechanisms.

BACKGROUND: Absolute coronary flow velocity reserve (CVR) after stenting may remain abnormal as a result of several different mechanisms. Relative CVR (rCVR=CVR(target)/CVR(reference)) theoretically normalizes for global microcirculatory disturbances and facilitates interpretation of abnormal CVR. METHODS AND RESULTS: To characterize potential mechanisms of poststent physiology, CVR was measured using a Doppler-tipped angioplasty guidewire in 55 patients before and after angioplasty, after stenting, and in an angiographically normal reference vessel. For the group, the percent diameter stenosis decreased from 75+/-13% to 40+/-18% after angioplasty and to 10+/-9% (all P<0.05) after stent placement. After angioplasty, CVR increased from 1.63+/-0.71 to 1.89+/-0.55 (P<0.05) and after stent placement, to 2.48+/-0.75 (P<0.05 versus pre- and postangioplasty). After angioplasty, rCVR increased from 0.64+/-0.26 to 0.75+/-0.23 and after stent placement to 1.00+/-0.34. In 17 patients with CVR(stent) < or = 2.0, increased basal coronary flow, rather than attenuated hyperemia, was responsible in large part for the lower CVR(stent) compared with patients having CVR(stent) >2.0. In 8 patients with CVR(stent) <2.0, a normal rCVR supported global microvascular disease. The subgroup of 9 patients with CVR(stent) <2.0 and abnormal rCVR (16% of the studied patients) may require a pressure-derived fractional flow reserve to differentiate persistent obstruction from diffuse atherosclerotic disease or microvascular stunning. CONCLUSIONS: Although a majority of patients after stenting normalize CVR for the individual circulation (ie, normal CVR or normal rCVR), in those with impaired CVR(stent), the analysis of coronary flow dynamics suggests several different physiological mechanisms. Additional assessment may be required to fully characterize the physiological result for such patients to exclude remediable luminal abnormalities.

Aged↗

PubMedDate not supplied

[Cardiac transplantation. Operative risk factors].

An evaluation of the risks of heart transplantation, and in particular operative risk factors, should lead to optimal decision making in light of the lack of sufficient supply of transplantable organs. The optimal recipient for transplantation is the patient who will benefit best from the organ in terms of survival and quality of life and for whom the operative risk is the smallest. This study emphasized the preparing role of donors over 45, the poorer prognosis in recipients over 60, the situations limited by pulmonary resistance and the notion of retransplantation. The practical impact of these observations is of prime importance.

Adolescent↗

PubMedDate not supplied

Myocardial high-energy phosphate depletion in allograft rejection after orthotopic human heart transplantation.

The present study was designed to assess whether acute rejection affects myocardial energy content of the human orthotopically transplanted heart. Adenosine triphosphate content was measured in one tissue sample obtained during 46 routine right ventricular endomyocardial biopsies 6 to 455 days (98 +/- 110) after transplantation in 19 cyclosporine-treated transplant recipients. Tissue samples were immediately frozen in liquid nitrogen within 10 seconds after excision. Adenosine triphosphate analysis was performed with high performance liquid chromatography. Three groups of biopsy specimens were classified according to the standardized cardiac biopsy grading system. Group 1: Eight biopsy specimens without rejection; group 2: 24 biopsy specimens with mild rejection; group 3: 14 biopsy specimens with moderate or severe rejection. Graft systolic function evaluated by echocardiographic fractional shortening was in the normal range the day of biopsy. All patients had normal coronary angiograms within 1 month of the study. In the presence of mild rejection (grade 1A or 1B), adenosine triphosphate content was not significantly different from that of nonrejecting hearts (26.15 +/- 7.1 and 28.57 +/- 8.23 nmol/mg protein, respectively). By contrast, a significant decrease in adenosine triphosphate content was observed when moderate or severe rejection with focal or diffuse aggressive infiltrates were present (10.46 +/- 4.11 nmol/mg protein; p < 0.01 versus two other groups). In seven cases, sequential analysis showed a significant increase in adenosine triphosphate content after rejection therapy concomittant with histologic improvement: 10.19 +/- 2.9 before and 30.13 +/- 7.0 nmol/mg protein after treatment (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗