On-pump Cardiac Surgery Enhances Platelet Renewal and Impairs Aspirin Pharmacodynamics: Effects of Improved Dosing Regimens.

On-pump cardiac surgery may trigger inflammation and accelerate platelet cyclooxygenase-1 renewal, thereby modifying low-dose aspirin pharmacodynamics. Thirty-seven patients on standard aspirin 100 mg once-daily were studied before surgery and randomized within 36 hours postsurgery to 100 mg once-daily, 100 mg twice-daily, or 200 mg once-daily for 90 days. On day 7 postsurgery, immature and mature platelets, platelet mass, thrombopoietin, glycocalicin, leukocytes, C-reactive protein, and interleukin-6 significantly increased. Interleukin-6 significantly correlated with immature platelets. At day 7, patients randomized to 100 mg once-daily showed a significant increase in serum thromboxane (TX)B2 within the 24-hour dosing interval and urinary TXA2 metabolite (TXM) excretion. Aspirin 100 mg twice-daily lowered serum TXB2 and prevented postsurgery TXM increase (P < 0.01), without affecting prostacyclin metabolite excretion. After cardiac surgery, shortening the dosing interval, but not doubling the once-daily dose, rescues the impaired antiplatelet effect of low-dose aspirin and prevents platelet activation associated with acute inflammation and enhanced platelet turnover.

Cardiopulmonary support during electrophysiological procedures for ventricular tachycardias not haemodynamically tolerated.

The objectives of this study were to evaluate the efficacy of percutaneous cardiopulmonary support (CPS) for circulatory assistance during electrophysiological endocavitary procedures for ventricular tachycardia (VT) in high-risk patients. From January to June 1999, eight patients with VT not haemodynamically tolerated, underwent an electrophysiological mapping and ablation while supported with percutaneous CPS in the cardiac surgery service of the University of Milan. The CPS system allowed for the maintenance of an arterial pressure of 60-70 mmHg during the tachycardia episodes. CPS was used for 10-20 min periods to restore haemodynamic stability. With the haemodynamic support of CPS, it was possible to target and induce 21 VTs, with a mean cycle of 325 ms. The mean support time was 140 min (120-160 min). Stabilization of the arterial pressure at a mean value of 65 mmHg (55-85 mHg) was achieved over a mean period of 26 seconds. Oxygen saturation remained over 90% throughout the support for all patients, with no blood gas or electrolyte abnormalities. No CPB-related complications were observed. In conclusion, percutaneous CPS guarantees effective haemodynamic support during mapping and ablation of VTs not haemodynamically tolerated, with no complications related to the extracorporeal circulation or the cannulation.

Off-pump redo coronary artery bypass grafting: technical aspects and early results.

BACKGROUND: Redo coronary artery bypass grafting (CABG) represents an high-risk surgical procedure, because of an increased incidence of perioperative death, myocardial infarction and stroke. Theoretically, the avoidance of cardiopulmonary bypass may reduce surgical traumatism and ameliorate early results. MATERIALS AND METHODS: From January 1995 to May 2001, we performed 123 redo CABGs, of which 53 (44%) off-pump. Off-pump procedure represented respectively 90% of redo CABG in the period 2000-2001 versus 30% in the 1995-1999 period. The mean age was 66.4 years, males were 39 (73%). The mean 2D-echo ejection fraction was 56% and in 9 cases (17%) was less than 40%. Three operations (5.6%) were performed on an urgent base. The access was median sternotomy in all cases. The mean number of grafts per patient was 1.9 (1.7 in the period 1995-99 vs. 2.3 in the period 2000-01, p=0.01). In 20 cases (38%) we grafted the circumflex artery branches (19% in the period 1995-99 vs. 55.5% in the period 2000-01, p=0.015). Improvements in surgical techniques were achieved over time. The current operative strategy includes the use of deep traction stitches in the posterior pericardium and wall stabilizers to expose target vessels, coronary intraluminal shunts during construction of the anastomoses and continuous trans-esophageal echocardiographic monitoring. Urgent conversion to on-pump procedure was not required in any case. RESULTS: We recorded no in-hospital death, one perioperative myocardial infarction (1.9%), one fifth postoperative day-stroke (1.9%) and 9 atrial fibrillations (17%). Mediastinal re-exploration for bleeding was performed in no one patient; 13 patients (24.5%) required postoperative blood transfusion. The mean length of postoperative stay was 7.5 days, ranging from 6 to 18 days. CONCLUSIONS: In our experience off-pump redo CABG is a safe and effective alternative to on-pump procedure and now off-pump is our first choice-technique in redo CABG. A complete revascularization is technically feasible with a low incidence of perioperative complications.

[Myocarcial revascularisation without extracorporeal circulation: current indications, surgical technique and results]. / La rivascolarizzazione coronarica senza circolazione extracorporea. Indicazioni attuali, tecnica chirurgica e risultati.

BACKGROUND: This study was undertaken to assess our experience of the evolution, over time, of beating heart surgery in the Cardiologic Center Foundation Monzino. METHODS: From March 1995 to June 2000, 506 patients underwent myocardial revascularization on beating heart: 313 until May 1999, and 193 between June 1999 and June 2000, after the advent of coronary artery stabilizers and shunts, to keep the surgical field bloodless, with minimal motion and continuous myocardial perfusion. Surgical accesss was via a median sternotomy for 408 cases and via a left anterior thoracotomy for 98 cases. RESULTS: The indications by choice increased, from I to II period, from 61% to 83% with special situations in which patients had three-vessel coronary artery disease raised from 33% to 50%, concerning also bypass grafts performed on circumflex artery and right coronary increased. Postoperative mortality in hospital decreased from 1.3% to 0.5% and perioperative IMA (acute myocardial infarction) from 3.8% to 0.5% in patients undertaken to median thoracotomy. Hospital stay decreased from 8 to 7 days about [no significant differences with patients who underwent CPB (cardiopulmonary bypass)]; in patients who underwent to MTS (left anterior minithoracotomy) there was no deaths, IMA decreased from 3.9% to 0% and hospital stay from 6 to 5 days. Grafts patency increased from 92.3% to 100%. CONCLUSIONS: To perform completed revascularisations is possible now even on the beating heart, and also to make precise anastomosis as on pump CABG, in a reproducible and easy way. The beating heart procedure, that is also more economical, might be expanded to all patients, not only high risk patients.

Centrifugal pump and reduction of neurological risk in adult cardiac surgery.

This study was performed to assess if the kind of pump used for CPB (roller vs. centrifugal) can influence neurological outcomes of adult cardiac surgery patients. Between 1994 and 1998, 3438 patients underwent coronary and/or valve surgery at our hospital; of these, 1805 (52.5%) underwent surgery with the use of a centrifugal pump, and 1633 (47.5%) were operated with a roller pump. The effect of the type of the pump and of common preoperative and intraoperative risk factors for five different neurological outcomes (permanent neurological deficit, coma, delirium, transient neurological deficit, overall neurological complications) were assessed with univariate and multivariate analyses in the whole patients population, in patients > or = 75 years old and in patients with histories of previous neurological events. Centrifugal pump use was the only protective factor for perioperative permanent neurological deficit in multivariable models developed for the whole patient population and for patients > or = 75 years old. In addition, it resulted as the only protective factor for perioperative coma occurrence in multivariable models developed for patients > or = 75 years old, and for patients with histories of previous neurological events. The use of the centrifugal pump provided a risk reduction for the considered events ranging from 23 to 84%. Centrifugal pump use can be helpful in reducing the occurrence of some of the most feared neurological complications of adult cardiac surgery patients.

Proteolysis of von Willebrand factor and shear stress-induced platelet aggregation in patients with aortic valve stenosis.

BACKGROUND: Excessive bleeding may complicate congenital cardiac defects. To explain the pathogenesis of this abnormality, we evaluated selected parameters of primary hemostasis in patients with aortic valve stenosis before and after corrective surgery. METHODS AND RESULTS: We examined shear-induced platelet aggregation with the filter aggregometer test and von Willebrand factor (vWF) structure by evaluating the multimeric distribution and extent of subunit proteolysis. The platelet count was reduced before corrective surgery, and shear-induced platelet aggregation was impaired. Moreover, vWF multimers of higher molecular mass were decreased, and proteolytic subunit fragments were increased. After correction of the cardiac defect, all of these parameters returned to normal. CONCLUSIONS: Alterations of vWF and platelet function may contribute to the bleeding diathesis in patients with aortic valve stenosis. Improvement after corrective surgery suggests that the passage of blood through a stenosed aortic valve may result in shear forces that induce vWF interaction with platelets in the circulation and, in turn, trigger platelet clearance, vWF degradation, and the impairment of primary hemostasis.

The radial artery: which place in coronary operation?

Previous long-term studies have shown unsatisfactory patency of saphenous vein grafts, compared with internal mammary artery grafts. Recently, the use of the radial artery as a coronary artery bypass graft has enjoyed a revival, on the basis of the belief that it will help improving long-term results of coronary operations. The recent report of encouraging 5-year patency rates, supports its continued use as a bypass graft. In this paper, we review the current knowledge about the radial artery as a bypass graft, with special emphasis on the clinical results.

Mid-term follow-up of 183 arterial myocardial revascularization procedures.

OBJECTIVE: To evaluate the mid-term results of complete arterial myocardial revascularization performed with arterial conduits. METHODS: From July 1987 to December 1994, 183 patients underwent a myocardial revascularization procedure with the use of at least two arterial grafts (IMAs, rGEA, IEA) at our institute. Their mean age was 56 +/- 8.7 years, the redo-operation rate was 16.9% (31/183), two-vessel disease was present in 61 patients (33.3%), three-vessel disease in 122 (66.7%). RESULTS: The LIMA was used in 179 patients (97.8%), the RIMA in 116 (63.4%), the rGEA in 66 (36.1%) and the IEA in 41 (22.4%). In-hospital mortality was 1.1% (2/183), while the perioperative myocardial infarction (MI) rate was 2.2% (4/183). The angiographic restudy, performed on 87 (47.5%) patients during the early postoperative period (median 38 days) showed the following grafts patency rates: LIMA 98.8 (86/87), RIMA 97.1 (34/35), IEA 85.7 (24/28), rGEA 97.05 (33/34) and saphenous vein 90.9% (10/11). The median follow-up was 35 months. Kaplan-Meier survival was 96 +/- 2% at 3 and 5 years, freedom from angina 94 +/- 2% at 3 years and 91 +/- 3% at 5 years, while the Kaplan-Meier freedom from cardiac events was 90 +/- 3% at 3 years and 88 +/- 3% at 5 years. Cox regression analysis identified perioperative MI (P = 0.03, relative risk 3.6) as the only prognostic factor for mortality at follow-up. With regards to recurrence of angina, multivariate analysis has shown that incremental risk factors for the return of angina are redo-operation (P < 0.01, relative risk 2.7) and the persistence of hypertension after surgery (P < 0.01; relative risk 3.2), while the use of the RIMA in the operation has emerged as a protective factor (P = 0.02; relative risk 0.43). Finally, only redo-operation (P < 0.01; relative risk 2.3), has emerged as a predictor of cardiac complications. CONCLUSION: Myocardial revascularization with at least two arterial grafts can be performed with very low perioperative morbidity and mortality and good mid-term follow-up. The mid-term results of arterial myocardial revascularization are less favourable in cases of redo-operations or when the RIMA is not used.

Myocardial revascularization procedures on multisegment diseased left anterior descending artery: endarterectomy or multiple sequential anastomoses (jumping)?

Complete revascularization is the primary goal in coronary surgery because of its superior long term results. However, in some patients the extent of the coronary artery disease is such that the usual coronary bypass technique may not allow to perform a complete myocardial surgical revascularization and, consequently, a satisfactory myocardial perfusion: so complementary revascularization techniques may become mandatory, especially when the diseased vessel is LAD or its branches. As a consequence, alternative procedures should be undertaken: coronary endarterectomy (EA) and multiple sequential anastomoses on a single vessel (jump), which guidelines are actually somehow controversial. Between January, 1989, and May, 1992, 53 patients underwent a myocardial revascularization procedure on LAD system unsuitable for single distal bypass; of them 35 (66%) underwent coronary endarterectomy, while in 18 (34%) multiple sequential anastomoses (jumping) were performed on the same vessel. About preoperative variables, average NYHA class (2.7 jump vs 2.1 EA group, p < 0.05), the history of more than 1 myocardial infarction (22.2% jump vs 2.9% EA, p < 0.04) and the presence of preoperative nitrates e.v (33.3% vs 8.6%, p < 0.04) were statistically higher in the jump group, suggesting a more unstable clinical status, while other clinical echocardiographic and catheterization features were not statistically different. For what operative and postoperative features are concerned, the number of anastomoses performed was statistically higher in the jump group, as exasperated (3.8 vs 2.7, p < 0.002) while perfusion (138 vs 141 min) and crossclamp time (103 vs 106 min) were similar. Furthermore we found a statistically lower incidence of perioperative myocardial infarction (0% jump is 22.8% EA group, p < 0.04); the postperfusion inotropic drugs requirement (22.2% vs 37.1%), the need of an intraaortic counterpulsation (0% vs 2.9%) and the in-hospital mortality (0% vs 5.7%) were lower in the jumping group too, also if they didn't reach statistical significance. Our experience suggest, also with the limits imposed by a retrospective case review and by a low number of cases reported, that myocardial revascularization of a multisegment diseased LAD system may be safely performed with the jumping technique with a low incidence of postoperative complications: it should be the first choice technique when conventional revascularization procedures are not enough to achieve complete myocardial revascularization. We advocate the use of EA technique only in that cases characterized by a diffuse atherosclerotic core and a well delimited plane of dissection, associated to a very poor runoff, which really excludes any chance to multiple anastomoses.

Role of right gastroepiploic artery in myocardial revascularization with arterial grafts.

Between July 1990 and December 1992. 112 patients underwent myocardial revascularization with arterial grafts in the Department of Cardiac Surgery, University of Milan. Monovascular patients were excluded from the study. The right gastroepiploic artery was used in 44 patients (39.3%); mean age was 54.3 years and reoperation rate 18.2%. Of the 44 patients, previous myocardial infarction had occurred in 25 (57%). Emergency operation was performed in one case (2%). Mean left ventricular shortening fraction was 36% and mean ejection fraction 58.6%. Coronary artery disease was bivascular in 10 patients (23%) and trivascular in 34 (77%). The arterial revascularization in patients with gastroepiploic artery was performed using a left internal thoracic artery graft in all 44 patients; the right internal thoracic artery was used in 18 (41%) and the inferior epigastric artery in two (4%). The sites of gastroepiploic artery grafting were 55% posterior descending, 16% right coronary artery, 11% posterolateral branch, 14% circumflex and in 4% posterior descending and posterolateral as sequential graft. No patient died; postoperative myocardial infarction rate was 4%. No complications related to gastroepiploic artery utilization were noted. Forty-three (98%) of the gastroepiploic artery group underwent graft reinvestigation: the arteries were correctly visualized in 41 patients (95%) and were patent in 39 cases and stenotic in two. A mid-term postoperative stress test (mean 17.4 months) was performed in 91% of patients. Normal limits were found in 37 patients (92.5%) and an abnormal stress test result in three (7.5%). The contemporary follow-up showed no deaths or myocardial infarctions. Three patients (7%) had recurrent angina. The role of gastroepiploic artery in arterial revascularization has become fundamental, especially, it is believed, for the posterior or posterolateral left ventricular wall. The present data show the patients to be clinically and functionally well 1 year after operation.

Midterm angiographic study of five recycled mammary arteries during four coronary redos.

BACKGROUND: Recently the technical feasibility of reusing the left internal mammary artery (IMA) in coronary artery reoperation has been documented, but the patency of "recycled" IMAs has not yet been established. METHODS: In 4 patients undergoing coronary reoperation, five internal mammary arteries (3 left IMAs and 2 right IMAs) that were patent but severely stenotic at the anastomotic site were taken down and reused. In 2 cases the IMAs were reanastomosed to the same target coronary artery, in 2 cases the IMAs were rerouted to another coronary artery, and in 1 case an interposition of a short segment of the greater saphenous vein was needed to reach the target coronary artery. RESULTS: Angiographic midterm evaluation, performed between 7 and 35 months postoperatively, showed patency of all the reused grafts without stenoses. CONCLUSIONS: When feasible, recycling of the IMAs may be considered if one or both IMAs have been previously used and are stenotic in the perianastomotic area, or when there is a stenosis in the native coronary artery distal to the anastomosis itself.

Pedicled arterial grafts in coronary surgery: postoperative echo color-Doppler study.

In 1994 a mid-term postoperative echo color-Doppler ultrasound was performed to check the pedicled arterial conduits used in coronary surgery, such as the left and right internal mammary arteries (LIMA, RIMA) and the right gastroepiploic artery (RGEA). This evaluation was made in 31 patients with a previous nonemergent complete arterial myocardial revascularization. The pedicled arterial grafts studied were 71 (31 LIMA, 15 RIMA and 25 RGEA). The Doppler spectrum (combined systolic/diastolic waveform), the diameter and the flow of every arterial graft was always identified (100% of detection) and there was a statistical significative difference between mean RGEA flow versus mean LIMA and RIMA flow (p<0.05). All the conduits studied were characterized by a good diastolic and end-diastolic velocity, evidence of normal graft patency. The postoperative angiogram of the LIMA, RIMA and RGEA conduits was performed in 27/31 (87.1%) patients and it showed 100% patency of arterial grafts used and of anastomoses. The echo color-Doppler data were compared to postoperative angiographic results. The echo color-Doppler imaging of the pedicled arterial grafts used in coronary surgery seems to be a promising technique for the postoperative serial assessment of the LIMA, RIMA and RGEA conduit function, because it is noninvasive, safe, easy, quick to perform and the preliminary results of echo color-Doppler ultrasound versus angiography are satisfactory.

[A case of complete myocardial revascularization with different arterial grafts: right internal mammary artery, right gastroepiploic artery and inferior epigastric artery]. / Un caso di rivascolarizzazione miocardica completa mediante tre differenti condotti arteriosi: arteria mammaria interna destra, arteria gastroepiploica destra, arteria epigastrica inferiore.

It has been well established that the internal thoracic artery (ITA) is a good alternative to the saphenous vein as conduit for coronary artery bypass grafting because of superior early and late patency. Many surgeons now commonly use both ITAs for CABG and many have adopted complex grafting methods such as free ITA graft and sequential anastomosis; despite these techniques, it's not always possible to achieve complete revascularization with arterial conduits. More recently the right gastroepiploic artery (rGEA) and the inferior epigastric artery (IEA) have been used as alternative arterial conduits. The authors report the experience of a case of myocardial revascularization in a patient with angina not responsive to medical therapy, severe tri-vessel coronary artery disease, which had a previous total bilateral saphenectomy; the patient was also found to have a right fibrothorax. In the surgical strategy the authors considered that the bilateral use of mammary artery could have been the cause of the depressed respiratory function and that it was important to leave intact the left hemithorax; they therefore employed the rITA in the revascularization of the anterior descending (AD). To complete the revascularization they used the IEA for a marginal branch of the circumflex artery and the rGEA for the interventricular posterior artery, branch of the right coronary artery. In this fashion good early results were obtained with absence of perioperative complications with a good life expectancy.

Preoperative management and surgical therapy in complicated acute infective endocarditis: a 5-year experience.

Twenty-five patients underwent early and elective valve replacement for infective endocarditis during a 5-year period between April 1985 and March 1991. Indications for urgent surgical intervention performed at a mean 32 (range 6-47) days after admission were intractable heart failure, systemic emboli, septic multiorgan failure and the presence of vegetations. Indication for elective surgery was persistent (mean 42 (range 17-56) days) infection after appropriate antibiotic therapy. Twenty patients (80%) had a native valve endocarditis; five (20%) had prosthetic valve involvement. A total of 30 valvular prostheses were implanted: 22 (73.3%) were aortic (21 mechanical and one biological); eight (26.7%) were mitral (all mechanical). All unstable patients referred were treated before surgery in the intensive care unit and subjected to blood ultrafiltration to restore satisfactory circulatory parameters. No patient underwent cardiac catheterization; all patients were operated upon on the basis of echocardiographic data alone. One patient (4%) died during hospitalization; two (8%) died later at 48 and 12 months after the first intervention. The reoperation rate was 12%. After a mean follow-up of 49 (range 1-71) months, 21 of the survivors (95%) were in New York Heart Association functional class I or II; the actuarial 5-year survival rate was 87%. Precise preoperative assessment of early operative indications and timely association of medical therapy in unstable patients could represent a step forward in the treatment of acute infective endocarditis.

Role of dipyridamole-echocardiography test in the evaluation of coronary reserve after coronary artery bypass grafting.

The object of this study was to assess the usefulness of the dipyridamole-echocardiography test in the early evaluation of coronary artery bypass grafting, when the use of an exercise stress test is precluded. We studied 39 consecutive patients (37 men and two women, mean age 57.3 years) referred to our institute for elective coronary artery bypass. Five patients had single, 12 patients double, 20 patients triple vessel disease, and two had left main stem disease. Nineteen left internal mammary artery grafts, 20 sequential grafts, and 39 single vein grafts were performed. All the patients were subjected to the test before (time range 1 to 3 days) and after (time range 6 to 10 days) the operation in the absence of therapy. Dipyridamole was administered intravenously 0.56 mg/kg over 4 minutes (low dose); if no effect was apparent, an additional 0.28 mg/kg over 2 minutes (high dose) was given. During the test, blood pressure and a twelve-lead electrocardiogram were monitored. An arbitrary wall motion score was derived by dividing the left ventricle into six regions and grading from 0 to 3-normokinetic, hypokinetic, akinetic, and dyskinetic zones. Preoperatively the test was positive in 38 patients as evidenced by wall motion abnormalities (36 patients had electrocardiographic changes) and in one patient by electrocardiographic changes and chest pain; 22 tests were positive after the low dose and 17 after the high dose. Angina was present in 33 patients. Mean wall motion score was 1.64 per patient in the basal condition and 4.03 per patient after the test (p less than 0.001). After coronary bypass in three patients the test was positive at the same dosage that was used preoperatively, as shown by wall motion abnormalities (in two patients by electrocardiographic changes, as well). Four patients had symptoms. Furthermore, at 6 months' follow-up, a treadmill stress test performed in these three patients was positive for ischemia and angina. The wall motion score was 1.25 per patient in the basal condition and 1.53 per patient after the test (no significant difference). When the preoperative wall motion score obtained after dipyridamole echocardiography was compared with the postoperative score, a statistically significant difference was seen: 4.03 per patient versus 1.53 per patient (p less than 001). In eight patients we observed an improvement of basal myocardial contractility after the operation, which indicates the reversibility of wall motion abnormalities observed before coronary bypass. In conclusion our data show that the dipyridamole-echocardiography test is a suitable method for the early assessment of bypass grafting when other methods, exercise dependent, are not indicated.(ABSTRACT TRUNCATED AT 400 WORDS)