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Biomedical subjects

C M Grondin

Publications and source records attributed to C M Grondin.

At least 37 records · Page 2Linked to original sources
PubMed1980

Myocardial protection through cold cardioplegia using diltiazem, a calcium channel blocker.

During two hours of aortic clamping, two groups of 10 dogs each were given an intermittent infusion of a cold solution in the aortic root. In one group, the solution contained 20 mEq per liter of potassium chloride (KCl) and in the other, a calcium channel blocker (diltiazem). Left ventricular (LV) performance was measured by calculation of LV pressure, left ventricular end-diastolic pressure (LVEDP), cardiac index (CI), and stroke-work index (SWI). Regional myocardial function was assessed through ultrasonic crystals implanted in the subendocardial areas of both the left anterior descending (LAD) and circumflex coronary arteries. Dogs receiving KCl displayed deterioration of LV performance as evidenced by a return of maximal LV pressure, maximal rate of rise of LV pressure (dP/dtmax), CI, and SWI to 74 +/- 4%, 87 +/- 5%, 74 +/- 6%, and 59 +/- 6%, respectively, of the initial (before clamping) values. Animals that received diltiazem, on the other hand, had for the same variables a return to 85 +/- 4%, 99 +/- 7%, 129 +/- 8%, and 111 +/- 10% of the initial values. The rate of relaxation (peak negative dP/dt) decreased in both groups but less in dogs receiving diltiazem. Regional function in the area of the LAD and circumflex arteries showed little change in either group. We conclude that cold cardioplegia with a solution containing KCl or diltiazem protects the myocardium during prolonged ischemic cardiac arrest. Return of LV function on the whole is superior when diltiazem is used.

Animals↗
PubMed1980

MB creatine kinase and the evaluation of myocardial injury following aortocoronary bypass operation.

Myocardial injury was studied in 104 patients undergoing coronary artery grafting without cold chemical cardioplegia using the quantity of the isoenzyme MB of the creatine kinase liberated as an indicator. This method of evaluation, which is said to permit comparison of different techniques of myocardial protection, allowed us to consider the relative importance of several factors believed to have an influence on intraoperative myocardial injury. Indices of significance were duration of symptoms before operation, presence of chronic arterial hypertension, and the type of antiangina treatment employed. Other operative factors included severity of the arterial lesions, number of anastomoses performed, and duration of extracorporeal circulation and of aortic cross-clamping.

Angina Pectoris↗
PubMed1980

[Recurrent angina after coronary surgery. Results of reoperations for myocardial revascularization].

40 patients presented with invalidating angina after initial revascularisation surgery (44 operations). The relapse of angina was attributed to thrombosis or stenosis of the graft (33 p. 100), graft failure plus the presence of non-bypassed coronary lesions (progression of coronary artery disease or incomplete initial revascularisation) (52 p. 100) or to the presence alone of coronary lesions which had not been bypassed (15 p. 100). At reoperation 37 stenosed or thrombosed grafts were replaced or repaired and 36 new aortocoronary bypasses were implanted. The perioperative risk was comparable to that of the initial operation (4,5 p. 100 mortality, 13,6 p. 100 myocardial infarction). The long term clinical improvement (34 months) was however less satisfactory (30 p. 100 unimproved). Several factors may account for the relatively high failure rate: the incidence of incomplete revascularisation; perioperative myocardial infarction and, above all, rapid progression of the coronary artery disease. Reoperation for myocardial revascularisation should therefore be restricted to patients with severe angina despite medical therapy, in whom the angiographic appearances suggest that optimal revascularisation might be possible.

Adult↗
PubMed1979

Reoperation for coronary graft failure: clinical and angiographic results in 43 patients.

Reoperation because of early or late coronary graft failure was performed in 43 patients who were part of a group of 1,985 patients operated on for coronary artery disease and followed for up to 7 years. Considerable variation in the results was noted depending on whether the patients were symptomatic or not before reoperation. Of the symptomatic patients, 85% were asymptomatic late (30 months) after reoperation whereas of those patients reoperated on despite the apparent lack of symptoms, 71.5% remained free from angina later on. Moreover, patency rate was high (94.4% or 17/18 grafts) in the first group and much lower (38.4% or 5/13 grafts) in those reoperated on solely on the basis of an early angiogram showing malfunctioning grafts. Patency rate was higher when the graft was totally replaced (92.3% or 12/13 restudied) rather than repaired simply through interposition of a segment of vein (37.5% or 3/8). It is apparent that results of reoperation in symptomatic patients are identical to those of an initial revascularization. On the other hand, patients who are asymptomatic despite early evidence of malfunctioning grafts should be reoperated on only when optimal angiographic conditions are present, that is, a coronary artery that is a good size, severely narrowed, and supplying a large myocardial area.

Angina Pectoris↗
PubMed1979

Prophylactic coronary artery grafting in patients with few or no symptoms.

Fifty-five patients who underwent prophylactic coronary artery grafting were followed for 4 to 8 years. Sixteen patients had no angina, and 39 were in New York Heart Association Functional Class I. Twenty-one patients had single-vessel disease, 13 had double-vessel disease, and 27, triple-vessel disease. A total of 101 grafts were inserted. There were no operative deaths. Two patients suffered a perioperative myocardial infarction (MI), and 3 were reoperated on for persistent bleeding. Early after operation, 9 of the 45 grafts were occluded. At 1 year, 2 patients had occlusion of all grafts, and 1 had similar findings at 5 years. There were 4 late deaths, 3 related to coronary artery disease. Seven patients sustained a late MI. Thirty-one of the 51 survivors (60.8%) seen late (mean, 69.3 months) after operation were free from angina; 14 were in Class I and 6, Class II. It is apparent from this retrospective study that patients such as these stand to benefit little from prophylactic revascularization. Longevity may be increased, however, in patients who are asymptomatic after MI.

Adult↗
PubMed1979

Loss of the improvement of angina between 1 and 7 years after aortocoronary bypass surgery: correlations with changes in vein grafts and in coronary arteries.

Improvement of effort angina following pure aortocoronary bypass graft surgery was related to postoperative control angiographic studies of grafts and coronary arteries in 75 unselected patients. Clinical and angiographic evaluations were carried out at approximately 1 year and at 5 to 7 years after surgery. At 1 year, 61 (81.3%) were improved (52 without angina and 9 with partial improvement by at least two functional classes), whereas 14 were unimproved (18.7%). At approximately 6 years, loss of improvement (reappearance of angina or aggravation by at least two functional classes) was observed in 22 of the 61 improved patients, representing an attrition of 36.1% over a 5-year period. Graft occlusion or a narrowing of over 50% was observed in two of the 39 patients in whom improvement had continued (5.1%), whereas it was found in six of the 22 patients (27.3%) whose results deteriorated (p less than 0.05). Similarly, progression to occlusion of a preexisting stenosis of over 50% or appearance of a new stenosis of over 50% in a major coronary artery (distal to a graft or in an unbypassed artery) was observed in five of the 39 patients with continued improvement (12.8%) and in 11 of the 22 patients whose condition deteriorated (p less than 0.01). Changes in a graft or in a coronary artery were noted in 63.6% (14/22) of the patients with loss of improvement as compared to only 18% (7/39) of the patients whose improvement did not deteriorate. Improvement of angina was also evaluated in all survivors among our first 500 cases who had preoperative effort angina and pure bypass surgery with or without angiographic studies. Of these 260 patients, 70.4% were angina-free or improved by two to three functional classes at 1 year, and only 41.9% at 7 years after surgery. It is concluded that the effect of aortocoronary bypass graft surgery is transient in a high proportion of patients and that deterioration of results is related to late graft modifications and progression of atherosclerosis, particularly in ungrafted coronary arteries.

Adult↗
PubMed1978

Aortocoronary saphenous vein bypass graft changes 5 to 7 years after surgery.

Control angiographic studies were carried out 54 to 88 months after aortocoronary saphenous vein bypass surgery (70 +/- 10 months) in 100 unselected patients who were known to have at least one patent graft 6 to 18 months following the operation. Only 17 of the 159 grafts were found occluded during this interval of 5 years, giving an average yearly attrition rate of 2.1% after the first year. The mean yearly attrition rate was 0.7% in our second series of near consecutive patients operated on after 2 years of experience and modifications of surgical techniques, and it compares favorably with the 2.4% yearly attrition rate found in our first series of patients (P < 0.05). Of the 37 grafts having localized stenoses at 1 year, eight became occluded (21.6%), and four became worse. Grafts with localized stenoses were more prone to late occlusion, whereas no late occlusion was observed in normally appearing grafts at 1 year. Diffuse graft narrowing noted during the first year showed no further change during the subsequent 5 years, and it did not appear to lead to late occlusion. Finally, in 14 grafts, localized narrowing developed after the first year, at a yearly rate of 1.5%. Atherosclerosis appears to be the most likely etiology, being found in two of these instances at reoperation.

Coronary Angiography↗
PubMed1978

Optimal patency rates obtained in coronary artery grafting with circular vein grafts.

Twenty-two patients underwent coronary artery grafting with a circular vein graft comprising four or five distal coronary anastomoses. Postoperative angiographic evaluation showed patency in 90 (95.7 percent) of the 94 coronary anastomoses fashioned in this manner. All four occlusions occurred in the one patient whose graft comprised five anastomoses and was occluded beyond the first anastomosis on the right coronary artery (RCA). Eleven of the 94 anastomoses were made onto arteries with limited runoff. Blod flow averaged 214 ml. per minute (range 130 to 320) in the main portion of the graft and 59 ml. per minute (range 35 to 100) in the most distal segment. Flow doubled (averaged 403 ml. per minute) in the 11 grafts injected with papaverine. The technique of circular vein grafting is described in detail and potential pitfalls are outlined. The reasons for the high early patency rate are believed to be the following: (1) high flow in the proximal segment of the graft insuring patency of said segment, (2) termination on the left anterior descending (LAD) coronary artery providing good distal flow and patency. (3) diamond-shaped side-to-side anastomoses (SSA's) preventing angulation of the graft at these crucial points, and (4) nearly equidistant anchoring at the site of the multiple anastomoses giving the graft a smooth, even contour.

Coronary Artery Bypass↗
PubMed1978

Evaluation of myocardial damage during coronary artery grafting with serial determinations of serum CPK MB isoenzyme.

Serial determinations of creatine phosphokinase isoenzymes (CPK) were made during the operative period and the first postoperative week in 60 patients undergoing coronary artery bypass surgery. Electrocardiograms (ECG) and serum levels of glutamic oxaloacetic transaminase (SGOT) and lactic dehydrogenase (LDH) were also evaluated. All patients had increased CPK MB activity which first became detectable during the operative period. The CPK MB curves usually showed a peak during the first postoperative hours and then a rapid decay. Some curves, however, showed a different profile with a prolonged liberation of CPK MB. This type of curve was more frequent in patients with electrical signs of necrosis or ischemic injury. In this group, the total amount of CPK MB released was greater than that in patients with unchanged ECG tracings (p less than 0.05). A mean curve of CPK MB activity was calculated for the patients without electric and/or enzymatic signs of myocardial injury. Serum CPK MB determination is a useful technique for identifying perioperative myocardial infarction (MI) and the time sequence of its occurrence. The appearance of this isoenzyme in every patient undergoing coronary surgery is an interesting finding, and it significance needs to be clarified.

Adult↗
PubMed1977

Thromboembolic complications with the cloth-covered Starr-Edwards aortic prosthesis in patients not receiving anticoagulants.

A comparison of the incidence of thromboembolic (TE) episodes was made in three groups of patient who underwent aortic valve replacement with the cloth-covered Starr-Edwards prostheses. Group 1 consisted of patients who received anticoagulants for either the entire period of follow-up or for a period of variable duration, after which these agents were no longer administered. When anticoagulants were stopped, 22 patients were categorized as Group 3 for study. Group 2 comprised patients who never received anticoagulants. Of the 147 patients followed in Group 1, 14 suffered one episode of TE. Six patients experienced major emboli; 3 of them died. Twenty of the 82 patients followed in Group 2 (no anticoagulants) suffered TE complications. There were 10 episodes of major emboli. Five of the 22 patients in Group 3 suffered an episode (all major) of TE. It is concluded from this study that anticoagulants should be given permanently to all patients with cloth-covered Starr-Edwards prostheses. Indeed, there is no period after operation when the incidence of TE is so low that anticoagulation may be safely discontinued.

Acenocoumarol↗
PubMed1977

Sequential anastomoses in coronary artery grafting: technical aspects and early and late angiographic results.

The present study concerns itself with the early and late results obtained with aortocoronary vein grafts containing more than 1 coronary anastomosis per graft. The surgical technique is described in detail and some of the hazards are outlined. It is apparent that the use of side-to-side anastomoses (SSAs) leads to a marked increase in blood flow in the proximal portion of the graft (average flow,131 ml/min) and also increases the patency rate of the proximal anastomosis. Thus, 3 of 51 SSAs were obstructed on the early angiogram, and only 1 of the 28 SSAs restudied at one year had become occluded. Although the cumulative--early and late--patency rate (55/66, or 83.3%) of the distal end-to-side anastomoses (ESAs) was not significantly better than that usually seen with conventional vein grafts, it is believed that improvement in the technique and greater awareness of some of its pitfalls will further decrease awareness of some of its pitfalls will further decrease the occlusion rate of distal ESAs. Most occlusions of the ESA appeared related to angulation, which tended to occur in the segment of graft between the proximal and the distal anastomoses. Appropriate modifications in the technique are described that should help to eliminate this difficulty. The use of SSAs allows for grafting of small coronary arteries which, with the conventional single anastomosis technique, are not usually bypassed in view of the high expected failure rate. Thus, of the 9 SSAs performed to 1 mm arteries and studied on two occasions, 8 remained open early after operation and 7 were still patent a year later.

Aorta↗