Myocardial protection in diabetics with left main stem disease: which is the best strategy?

AIM: Diabetes mellitus is a well known risk factor for extensive coronary disease. The optimal route for cardioplegia administration in patients with severe ischaemic heart disease undergone surgery, especially with left main stem disease (LMSD) is still under debate. Aim of the study is to compare 2 different strategies of myocardial protection in diabetics with LMSD. METHODS: Between January 2000 and June 2003 90 consecutive patients with type II diabetes mellitus and LMSD undergoing isolated myocardial revascularization were divided into 2 groups according to the route of cardioplegia delivery: antegrade in 45 patients (group A), antegrade followed by intermittent retrograde in 45 (group B). ECG, Troponin I, MB-CPK, MB-CPK mass were performed at 12, 24, 48, and 72 hours postoperatively. Echocardiography was performed preoperatively and before hospital discharge. RESULTS: Groups were homogeneous in preoperative and intraoperative variables, apart from higher incidence of unstable angina and longer cardiopulmonary bypass time in Group B and hypertension in Group A. Hospital deaths, in intensive care units (ITU) stay, perioperative acute myocardial infarction, intra-aortic balloon pump support, postoperative recovery of left ventricle ejection fraction and wall motion score index were similar in both groups. In hospital stay proved shorter in group B (p=0.002), whereas postoperative atrial fibrillation was higher in group A (p<0.001), as postoperative inotropic support (p=0.006). Troponin I proved significantly higher in group A from the 12 degrees to the 72 degrees postoperative hour (p<0.0001). CONCLUSIONS: Despite major in hospital end-points did not differ with strategy of cardioplegia administration, combined route of intermittent blood cardioplegia allows better biochemical and perioperative results in diabetics with LMSD.

Prosthetic valve obstruction: thrombolysis versus operation.

An acute obstruction is a life-threatening complication of mechanical valve prostheses, and is caused by the formation of fresh clot or fibrous tissue overgrowth, or both. Accurate selection of the most appropriate treatment for a particular patient is mandatory. From January 1991 to July 1992, 28 cases of prosthetic thrombosis were managed. Twenty patients underwent surgical treatment, with one operative death, and 8 patients were treated with thrombolysis using recombinant tissue-type plasminogen activator (rt-PA). The criteria for using thrombolysis were (1) the recent onset of symptoms, (2) transesophageal echocardiographic evidence of clots on the valve or cardiac chambers, and (3) preserved disc excursions. All patients who underwent thrombolysis had mechanical valves (two bileaflets, four tilting discs, and two ball valves); seven valves were in the mitral position and one was in the aortic. Symptoms of obstruction consisted of cardiac failure in 6 cases or thromboembolism in 5, or both. The mean interval between the onset of symptoms and the initiation of thrombolysis was 81 +/- 65 hours. After infusion of the rt-PA, normal valve function was restored in all patients, as documented by transesophageal echocardiography. No deaths or neurologic complications occurred; there was one episode of minor peripheral embolism. Thrombolysis using rt-PA may be the appropriate treatment in patients with primary thrombosis of mechanical valves, thereby avoiding the operation-related risks.

Stentless fresh pulmonary homograft in mitral position.

We report the implantation of a fresh, stentless pulmonary homograft in the mitral position as an attempt to treat the 2nd recurrence of prosthetic endocarditis in a 66-year-old man. The postoperative course was uneventful; early postoperative transesophageal echocardiography showed a competent valve with a gradient of 4.2 mmHg. Fifteen months postoperatively, transthoracic echocardiography showed a good functioning homograft with a competent valve and no recurrence of endocarditis.

Submitral left ventricular aneurysm. Report of 2 surgical cases.

Submitral left ventricular aneurysm most commonly occurs among the black population. Nevertheless, this lesion has been described among whites. We report 2 cases of submitral left ventricular aneurysm that we treated successfully by surgery. Case 1 is that of a 52-year-old Brazilian black man with a submitral left aneurysm and mitral incompetence. Case 2 is that of a 25-year-old white man with a history of recurrent stroke; his echocardiographic study showed a small submitral left ventricular aneurysm. Due to the growing incidence of submitral left ventricular aneurysm among the white population, we emphasize the importance of a targeted echocardiographic study in all patients with a history of embolic episodes in the absence of apparent risk factors for embolism.

Risk predictors of paroxysmal atrial fibrillation following aortic valve replacement.

BACKGROUND: Atrial fibrillation (AF) is the most frequently encountered arrhythmic complication associated with cardiac surgery. The aim of this paper was to identify the clinical predictors of AF occurrence following aortic valve replacement. METHODS: Three hundred and two patients were included in this study and divided into two groups according to the absence (SR group, 243 patients, mean age 55.6 +/- 15 years) or the evidence (AF group, 59 patients, mean age 63.8 +/- 11 years) of post-aortic valve replacement AF. Sixty-five perioperative variables (37 preoperative, 8 intraoperative and 20 postoperative) were considered. RESULTS: Post-aortic valve replacement paroxysmal AF occurred in 59 out of 302 patients (19%). At univariate analysis, post-aortic valve replacement AF was associated with advanced age, left atrial enlargement, preoperative episodes of paroxysmal AF, the use of a warm blood cardioplegic solution and normothermia, administration of inotropic agents, prolonged assisted ventilation but also with postoperative acidosis, electrolyte imbalance and atrioventricular and intraventricular conduction disorders. Stepwise forward multivariate logistic regression analysis identified age (p = 0.002, odds ratio--OR 1.04), left atrial enlargement (p = 0.004, OR 2.6), a prior history of paroxysmal AF (p = 0.0003, OR 10.9), and postoperative electrolyte imbalance (p = 0.01, OR 2.3) as independent correlates of AF, whereas the use of hypothermia appeared to be a protective factor (p = 0.0004, OR 0.26). CONCLUSIONS: According to our findings, post-aortic valve replacement AF seems to be associated with well-defined anatomical and electrical substrates generated by advanced age, increased left atrial dimensions, and a possible electrical remodeling consequent to prior repetitive episodes of paroxysmal AF. On these grounds, external factors such as postoperative electrolyte imbalance might enhance atrial ectopic activity and trigger postoperative sustained tachyarrhythmias, while the use of hypothermia might allow for better protection of the atrial myocardium against intraoperative ischemia.

[Our experience in treatment of the inhibition of demand pacemaker by muscle potentials (author's transl)]. / La nostra esperienza nel trattamento dell'inibizione del pacemaker a domanda da parte di miopotenziali.

The inhibition of demand pacemakers by muscular potentials is rarely described in the literature. The Authors have found an interference of the pectoralis muscle's electric activity with pacemakers in 4 patients suffering from occasional faints. Extending this study to a group of 10 asymptomatic electrostimulated patients, pacemaker's inhibition by sub-maximal contraction of pectoralis major muscle has been found in 9 of them. The 4 symptomatic patients have been operated displacing the battery near the sternum. The poor thickness of the pectoralis muscle's fibres suggested the treatment. The controls performed from 2 to 8 months respectively have shown disappearance of the symptoms.

[Mono and bidimensional echocardiographic control in patients surgically treated by abdominal apical conduit (author's transl)]. / Possibilita' di controllo ecocardiografico mono- e bidimensionale in pazienti operati di condotto apico-aortico addominale.

Creation of a double outlet left ventricle by means of an apical conduit may solve the problems related to left ventricular outflow tract obstructions which are not amenaable to conventional surgical management. Searching a diagnostic method easily applicable, repeatable and reliable, the results obtained with serial echocardiographic controls have been evaluated. This technique has shown to be of great value in answering several hemodynamic questions. An echocardiographic protocol has been developed for the follow-up of these patients.

Right intracavitary cardiac tumors. Surgical management.

The surgical treatment of 6 patients affected by right cardiac tumors is reported. Three of them showed a right atrial myxoma, 1 metastases from an occult embryonal carcinoma and 1 a leiomyosarcoma of the pulmonary artery. While clinical diagnosis was not reliable, the echocardiographic examination was able to assess the site of the tumor, supplying useful information for the anatomy and surgery in 5 cases out of 6; in one case, the diagnosis was reached intraoperatively. All the patients survived the surgical treatment: while those with atrial myxoma recovered completely, the others with malignant tumors died from metastases 5 to 10 months postoperatively. The importance of early diagnosis is stressed together with the role of surgery, which permits the recovery of cases with benign tumors and a longer survival of cases with malignant tumors.

[Cold agglutinins in a cardiosurgical patient: a successfully operated case]. / Agglutinine da freddo nel paziente cardiochirurgico: su un caso clinico operato con successo.

A technique is described for providing myocardial protection with cold cardioplegia in a patient with cold autoagglutinins. The operation was done in normothermia and the coronary system was perfused with a normothermic (+37 degrees C) NaCl 0,9% solution to remove the blood before in it introducing the cold (+4 degrees C) cardioplegic solution. With this technique, the patient underwent an uneventful operation to relieve right ventricular-outflow stenosis operation.

[Biennial experience with aortic valve homografts prepared and preserved in our bank and implanted on the left ventricular outflow tract in adult patients]. / Esperienza biennale con omoinnesti valvolari aortici preparati e conservati nella nostra banca ed impiantati sull'efflusso ventricolare sinistro in pazienti adulti.

A homograft bank was established in 1986 at the Institute of Cardiac Surgery of the Second University of Naples. Since then 163 aortic and pulmonary homografts have been collected, and mostly used for right ventricular outflow tract reconstruction (69 at our Institution and 14 at other Italian Centers). In March 1991 free aortic homografts were first implanted in the left ventricular outflow tract in adult patients with aortic valve and/or root disease, for a total of 15 implantations with a follow-up ranging between 3 and 19 months (mean 10 months). According to the literature and our data, operative mortality for such procedure is not higher than for ordinary aortic valve replacement. With regard to mid-term failure rate and complications, homografts are to be preferred as they don't require anticoagulation. Moreover the best indication to free homograft implantation is active aortic valve endocarditis, especially when annular abscesses are present. Reinfection rate is lesser in these patients compared to those with mechanical or bioprosthetic valves because homografts have no prosthetic material, allow exclusion of abscessual cavities from blood flow and do not require the fixation of a rigid prosthetic sewing ring in an infected, friable annulus. Finally short and mid-term haemodynamic evaluations of such patients are excellent for all the aforementioned reasons as well as for the homograft non obstruction rate.

Risk factors for pacemaker implantation following aortic valve replacement: a single centre experience.

OBJECTIVE: To identify perioperative clinical predictors of permanent pacemaker implantation following aortic valve replacement. DESIGN AND PATIENTS: Prospective cohort study on 276 patients submitted for aortic valve replacement: 267 patients (mean (SD) age, 57.5 (14) years) with no conduction disturbances, and nine patients (67.7 (5) years) with severe conduction disturbances requiring permanent pacing; 65 perioperative variables (38 preoperative, eight intraoperative, and 19 postoperative) were considered. RESULTS: Nine patients (3.2%) had irreversible second or third degree atrioventricular (AV) block requiring permanent pacing. Risk factors for permanent pacing identified by univariate analysis were: preoperative: additional valvar disease, aortic regurgitation, myocardial infarction, pulmonary hypertension, anaemia, use of digitalis; intraoperative: cardiac arrest; postoperative: cardiac arrest, conduction disturbances, electrolytic imbalance, angiotensin converting enzyme inhibitor use. Multivariate logistic regression analysis identified preoperative aortic regurgitation (p < 0.005; odds ratio (OR) 6.6, 95% confidence interval (CI) 1.6 to 12.2), myocardial infarction (p < 0.0005; OR 15.2, 95% CI 6.3 to 19.9), pulmonary hypertension (p < 0.005; OR 12.5, 95% CI 3.2 to 18.3), and postoperative electrolyte imbalance (p < 0.01; OR 4.5, 95% CI 1.3 to 6.4). CONCLUSIONS: Irreversible AV block requiring permanent pacemaker implantation is an uncommon condition following aortic valve replacement. Previous aortic regurgitation, myocardial infarction, pulmonary hypertension, and postoperative electrolyte imbalance should be considered in order to identify patients at increased risk for advanced AV block.