Roberto Gallotti

Linear Cryoablation of the Left Atrium Versus Pulmonary Vein Cryoisolation in Patients With Permanent Atrial Fibrillation and Valvular Heart Disease. Correlation of Electroanatomic Mapping and Long-Term Clinical Results

Background—The aim of this study was to clarify the role of pulmonary vein isolation (PVI) alone versus left atrial linear lesions in the treatment of permanent atrial fibrillation (AF) in patients with left atrial dilatation and valvular disease. The primary end point was to assess the persistence of sinus rhythm (SR) off antiarrhythmic drugs (AADs) at 2-year follow-up and to correlate clinical outcome with surgical results validated with electroanatomic mapping (EAM). Methods and Results—A total of 105 patients with permanent AF undergoing valve surgery were assigned to 3 different groups: in groups “U” and “7,” left atrial linear cryoablation was performed, whereas in group “PV” patients, anatomic cryoisolation of pulmonary veins only was performed. In groups U and 7, SR was achieved in 57% of patients, whereas it was achieved in 20% of PV patients during 2-year follow-up. In the first 51 patients, the ablation schemes were validated with EAM. The EAM showed that the U lesion was never obtained: in 59% of these patients, a complete 7 lesion was achieved instead; in the 7 group, a complete 7 lesion was present in 65% of patients, whereas a complete PVI was obtained in 71% of patients. Considering patients in whom a complete 7 lesion was demonstrated with the EAM, SR without AADs was achieved in 86% of patients, whereas only 25% of patients with complete PVI were in SR without AADs. Conclusions—In patients with permanent AF, left atrial dilatation and valvular heart disease linear lesions in the posterior region of the left atrium are more effective than PVI alone. With cryoablation, the surgical intent is fulfilled in only approximately 65% of the cases. Knowing the real anatomic and electrophysiological effects of surgical ablation is necessary to correctly interpret the clinical outcome.

Limited posterior left atrial cryoablation in patients with chronic atrial fibrillation undergoing valvular heart surgery

OBJECTIVES We sought to evaluate whether a limited surgical cryoablation of the posterior region of the left atrium was safe and effective in the cure of atrial fibrillation (AF) in patients with associated valvular heart disease. BACKGROUND Extensive surgical ablation of AF is a complex and risky procedure. The posterior region of the left atrium seems to be important in the initiation and maintenance of AF. METHODS In 32 patients with chronic AF who underwent heart valve surgery, linear cryolesions connecting the four pulmonary veins and the posterior mitral annulus were performed. Eighteen patients with AF who underwent valvular surgery but refused cryoablation were considered as the control group. RESULTS Sinus rhythm (SR) was restored in 25 (78%) of 32 patients immediately after the operation. The cryoablation procedure required 20 +/- 4 min. There were no intraoperative and perioperative complications. During the hospital period, one patient died of septicemia. Thirty-one patients reached a minimum of nine months of follow-up. Two deaths occurred but were unrelated to the procedure. Twenty (69%) of 29 patients remained in SR with cryoablation alone, and 26 (90%) of 29 patients with cryoablation, drugs and radiofrequency ablation. Three (10%) of 29 patients remained in chronic AF. Right and left atrial contractility was evident in 24 (92%) of 26 patients in SR. In control group, two deaths occurred, and SR was present in only four (25%) of 16 patients. CONCLUSIONS Linear cryoablation with lesions connecting the four pulmonary veins and the mitral annulus is effective in restoration and maintenance of SR in patients with heart valve disease and chronic AF. Limited left atrial cryoablation may represent a valid alternative to the maze procedure, reducing myocardial ischemic time and risk of bleeding.

Left main coronary arterial lesion after microwave epicardial ablation

We present a case of left main coronary arterial lesion in a 62-year-old man who had undergone mitral valve replacement and microwave epicardial ablation. On postoperative day 90, the patient had an anterior myocardial infarction. The coronary angiography displayed the diagnosis of the left main trunk lesion. A myocardial revascularization was urgently performed, the postoperative course was uneventful, and the patient was in sinus rhythm. The left atrial epicardial ablation represents the ultimate step in the surgical treatment of chronic atrial fibrillation; nevertheless, the left main trunk lesion may occur as an extremely severe complication. The incorrect placement of the microwave probe may be responsible for the development of critical coronary artery stenosis.

Use of the Valsalva graft and long-term follow-up.

OBJECTIVE The Valsalva graft is a specifically designed Dacron graft that, on implantation and pressurization, generates pseudosinuses of Valsalva. We reviewed a multicenter experience of the reimplantation procedure with the Valsalva graft in patients with aneurysms involving the aortic root. METHODS A total of 278 patients underwent valve-sparing aortic root replacement using the Valsalva graft at 4 different Italian cardiac surgery centers and were studied by clinical assessment and echocardiography. Of the 278 patients, 220 were men (79%), with a mean age of 56 ± 15 years. Of the patients, 42 (15%) had Marfan syndrome, 31 (11%) had a bicuspid aortic valve, 13 (5%) had acute aortic dissection, and 136 (49%) had grade 3 or 4+ aortic insufficiency. Concomitant cardiac procedures were performed in 78 patients (28%). Additional aortic leaflet repair was necessary in 25 patients (9%). The mean crossclamp time was 120 ± 27 minutes. RESULTS There were 5 (1.8%) operative and 5 (1.8%) late deaths. The mean follow-up was 52 ± 28 months (range, 2-112 months) and was 100% complete. The cumulative actuarial survival was 95.2% (268 patients). A total of 32 patients (11%) had grade 3 to 4+ aortic insufficiency, and 17 of these required late aortic valve replacement (range, 3-78 months). At 10 years of follow-up, the freedom from aortic valve reoperation rate was 91%, and the rate of freedom from residual aortic insufficiency not needing reoperation was 88%. CONCLUSIONS The reimplantation type of valve-sparing procedure can be facilitated by the use of the Valsalva graft and can be performed with satisfactory perioperative and midterm results. How an optimal root reconstruction will affect the second decade of follow-up has yet to be determined.

Clinical histopathology and ultrastructural analysis of myocardium following microwave energy ablation.

OBJECTIVE Due to weaknesses of conventional modes for treating atrial fibrillation (AF), surgical energy ablation methods and tools to cure AF have been under rapid development. One of these methods, microwave energy, is beginning to be applied clinically. The purpose of this study was to examine histology and ultrastructure of lesions produced by microwave energy in the myocardium. METHODS Fifteen consecutive patients underwent surgical microwave energy ablation (Microwave Ablation System with FLEX 4 probe, AFx Inc., Fremont, CA) concomitant to a valve procedure. Epicardial ablation was carried out on the beating normothermic heart prior to performing the valve procedure. Two tissue specimens (1cm(2)) were obtained from each patient; one from the lesion site (right appendage) and the other from an adjacent, non-ablated site, which was used as control. Tissue samples were fixed and stained as appropriate for histological and ultrastructural analysis. RESULTS All ablated samples revealed observable microscopic alteration, including loss of nuclei, foci of coagulative necrosis or induced irregular bands of contraction. Ultrastructurally, ablated cells demonstrated architectural disarray, loss of contractile filaments, mitochondrial swelling and focal interruption of plasma membrane. CONCLUSIONS Histologic appearance of lesions created by epicardial microwave energy ablation was consistent over tissue samples, although acute findings demonstrated differences from cryoablation. In most of the cases, lesions were transmural, as was demonstrated by loss of cellular viability throughout the depth of tissue specimens.

The Marfan Syndrome: Surgical Technique and Follow-up in 50 Patients

Fifty patients with Marfans syndrome underwent operation at the National Heart Hospital because of cardiovascular complications. Forty-six had an aneurysm of the ascending aorta, 13 had chronic dissection, and 6 had acute dissection of the aortic wall. Forty-three aortic valves were incompetent, and five were stenotic and incompetent. One mitral valve had minor regurgitation. The Starr-Edwards prosthesis was used in 36 patients, homograft valves in 4, fascia lata valves in 2, and xenograft valves in 6. The ascending aorta was replaced with a Dacron tube in 40 patients and with an aortic homograft in 2. Three patients required Dacron patches over the aneurysm, and 1 patient had plication of the aortic wall. Early mortality totaled 12% (6 patients). Only 1 of these patients died in the last five years. Reoperations for homograft incompetence, periprosthetic leak, and acute dissection of an unreplaced aorta resulted in 1 hospital death (33%). Forty-three patients have been followed for up to 8.5 years (mean, 3.5 years), with 7 late deaths (46.2%). The improvement in recent surgical results with decreased operative mortality supports an aggressive surgical approach to Marfans syndrome in view of the poor prognosis for the natural history of this disease.

Myocardial acute and chronic histological modifications induced by cryoablation

We use cryoablation as the treatment of choice for AF (atrial ®brillation): the technique consists of a linear cryoablation at 2608C connecting the four pulmonary veins and the posterior mitral lea ̄et. Incomplete ablation of atrial myocytes may be responsible for AF recurrence should cryoablation be incomplete (i.e. non-transmural) because of associated atrial hypertrophy [1]. In fact should any electrical path be spared, because of incomplete myocyte necrosis, the anomalous circuit could perpetuate in spite of the surgical treatment. For this reason we decided to evaluate in humans the acute and chronic histological modi®cations and the severity and the extent of the myocyte damage taking place in the atrial wall after cryoablation [2]. In four consecutive patients, operated on for mitral surgery, an atrial biopsy (1 cm) was taken from the right (two patients) or left (two patients) appendage once the heart was, respectively, canulated or already under cardioplegic arrest during cardiopulmonary-bypass (CPB) at moderate hypothermia. These locations were chosen because they are easily accessible and they would have European Journal of Cardio-thoracic Surgery 17 (2000) 339±340

Surgical approaches to atrial fibrillation.

Atrial fibrillation (AF) remains an unsurmounted hurdle toward the cure of supraventricular arrhythmias. Despite its high prevalence, a definitive treatment approach has not been established. AF is triggered in most cases by early premature atrial beats and is maintained by anomalies of the substrate. Elimination or modification of either one or both may be effective in the cure of AF. Surgical ablation, which originated with the favorable results of the Maze procedure developed by Cox, has an important role in the cure of AF associated with heart diseases that require cardiac surgery. This is due to the high success rate and to the simplification of the procedure now used which has resulted in reduction of the procedural time and complications. Various techniques have been proposed, however, it is noteworthy that the posterior part of the left atrium and the ostia of pulmonary veins are involved in all approaches despite the different energy sources used (radiofrequency or cryo energy) and the different design of the intended lesion. These results imply that the posterior part of the left atrium is crucial in the genesis and maintenance of atrial fibrillation. On the other hand, it is not clear if the results of the ablation are due to the linear lesions that modify the substrate or to the electrical isolation that eliminate the triggers. A thorough electrophysiological evaluation post ablation has been performed only in few cases. Greater understanding of the mechanism of success of surgical ablation may advance the development and success of other approaches. Considering that surgical ablation is usually performed in patients with permanent AF, linear lesions modifying the substrate together with pulmonary vein isolation have shown better results than the elimination of the triggers with a pure electrical isolation of the pulmonary veins. Prevention of AF recurrences has been relatively good, however some severe complications (atrioesophagus fistula, coronary artery damage, etc.) have been reported. Considering the relatively benignity of AF in absence of associated cardiopathy, the risk of complications should discourage widespread application of surgical ablation in patients with lone AF. On the contrary it should be routinely proposed in most patients with permanent or paroxysmal AF undergoing cardiac surgery.

Reoperation for Aortic False Aneurysms: Our Experience and Strategy for Safe Resternotomy

Abstract  Background and aim of the study: To review our experience with reoperation for aortic false aneurysms (FA) and to present an analysis of the relevant surgical approaches and risks. Methods: From May 1999 to June 2006, 11 patients underwent a total of 13 reoperations due to aortic false aneurysms, with an incidence of 3% of all thoracic aortic cases. Cardiopulmonary bypass (CPB) and cooling were started before sternotomy in all cases. Three different strategies were adopted for patients depending on the position of the FA in the mediastinum as indicated by a preoperative CT scan. These included: deep hypothermic circulatory arrest (18°C), moderate hypothermia (28°C), and mild hypothermia (32°C). In two patients, the sternotomy ruptured the FA causing profuse hemorrhaging. In all the other cases sternotomy was performed without complication. The repair consisted in simple repair by direct suture (10 cases) or extensive repair by refashioning the anastomosis (three cases). Results: Two hospital deaths occurred with a hospital mortality rate of 16.7%. Permanent neurological deficit developed in one patient. Transient neurological deficit in the form of left lower limb weakness was observed in one patient. False aneurysm recurrence developed in two cases. Among patients present at follow‐up (nine survivors), four are in NYHA class I and five in class II. Conclusions: Aortic false aneurysms carry a high mortality and morbidity rate. Nevertheless, we believe that selecting the right strategy according to the position of the FA in the chest can reduce surgical risk, thus permitting relatively safe resternotomy.

Left ventricular hemangioma

Cardiac hemangiomas are rare, primary benign cardiac tumors. The authors report their experience of diagnosis and treatment of an hemangioma localized into the left ventricle. The tumor could be successfully resected and there is no recurrence at 1 year follow-up.