Borst Hg

Thoracic aortic aneurysms after acute type a aortic dissection: Necessity for follow-up

Between April 1979 and May 1989, 86 patients underwent emergency operation for acute type A aortic dissection. Sixty-four (74.4%) survived. None of the survivors died of late aortic complications. Fifty-eight patients were followed 3 months to 10 years (mean follow-up, 3.2 years) postoperatively with computed tomography and digital subtraction angiography. Dilatation of the distal aorta (diameter size range, 6 to 10.5 cm) developed in 10 patients (17%). Six patients underwent replacement of the descending aorta 1 month to 21 months (mean period, 8.5 months) after aortic dissection repair. Two of them had third-stage thoracoabdominal replacement. In 2 patients, replacement of the descending aorta was scheduled; 1 died before reoperation and 1 refused the procedure. Two patients underwent aortic arch replacement; it is scheduled for another (fourth stage). There were no deaths among the patients having reoperation. The rate of indications for reoperation on the aorta downstream from the original repair 1 month to 6 years 4 months (median time, 9 months) after primary surgical intervention for acute type A aortic dissection was 24% (14 reoperations in 10 of 58 patients). This study underscores the importance of close follow-up of patients having operation for acute type A aortic dissection. Early recognition of progressive downstream aortic pathology permits effective prevention of aortic rupture and timely reoperation.

Inhibition of atrial fibrillation by pulmonary vein isolation and auricular resection : experimental study in a sheep model

OBJECTIVE The MAZE procedure has proven effective for surgically treating atrial fibrillation, but its acceptance has been limited due to the complex dissection pattern. A new simplified operative technique, that comprises two important components of the MAZE procedure, has been evaluated in an established animal model of induced sustained atrial fibrillation. METHODS In eight sheep, median sternotomy was performed for cardiopulmonary bypass via femoral and bicaval cannuiation. Bipolar atrial and ventricular electrodes (16) were applied for computerized EKG-sampling. Atrial fibrillation was induced during continuous theophylline infusion (0.5 mg/kg/min) by repetitive (10x) biatrial stimulation. Atrial response was monitored and mapped. The operative procedure was accomplished in induced ventricular fibrillation: Right and left atrial appendices were resected and a circumferential transmural incision around all pulmonary veins was performed and closed. After defibrillation, the atria were stimulated again using the above protocol and EKGs were sampled. RESULTS Sustained atrial fibrillation was inducible in all animals (80 stimulation episodes, median duration 31 s, 6 incessant episodes) prior to dissection. Post resection of the atrial appendices and pulmonary vein isolation, atrial fibrillation was not inducible in any of the eight animals (80 stimulation episodes). A significant interatrial (104 +/- 13 ms) and atrioventricular (208 +/- 19 ms) conduction delay was observed post dissection. CONCLUSION We conclude that the described procedure is effective for the inhibition of sustained atrial fibrillation in morphologically unaltered atria. The operative approach involves less dissection than the MAZE procedure, which could facilitate its use in concomitant mitral procedures. The clinical significance of the observed AV-Delay has to be evaluated.

The Role of Spinal Angiography in Operations on the Thoracic Aorta: Myth or Reality?

BACKGROUND The importance of preserving the artery of Adamkiewicz during replacement of the thoracoabdominal aorta is debated. We report our experience with the use of preoperative spinal angiography and modification of the surgical technique. METHODS Between September 1993 and March 1996, 46 patients (mean age, 57 years; range, 25 to 73 years) underwent spinal angiography at our institution, 23 for an aneurysm and 23 for chronic dissection. Localization of the artery of Adamkiewicz between T-9 and L-3 was successful in 30 (65%) patients: T-9, left = 2, right = 1; T-10, left = 4; T-11, left = 10, right = 2; T-12, left = 3, right = 1; L-1, left = 1, right = 2; L-2, left = 2, right = 1; and L-3, left = 1. Thirty-one patients subsequently underwent replacement of the descending thoracic aorta and 13 underwent replacement of the thoracoabdominal aorta. Left atrial-femoral artery bypass was used in 23 patients and full extracorporeal circulation was used in 20 patients. Twelve procedures included the reimplantation of crucial intercostal/lumbar branches. RESULTS The operative mortality rate was 6.8% (3 of 44 patients) and 1 (2.27%) patient had paraparesis. In addition to the 12 patients who underwent targeted reimplantation of the intercostal branches, evaluation of the spinal cord blood supply influenced the operative technique in 19 other patients. CONCLUSIONS Selective angiography can demonstrate the spinal cord blood supply even in patients with complex aortic pathology. It is a helpful tool for planning extensive replacement of the thoracic and thoracoabdominal aorta.

Advances in aortic arch surgery.

From 1980 to January 1991, 130 patients (89 men and 41 women, aged 22 to 76 years; mean age, 52 years) underwent 133 interventions on the aortic arch. Aneurysm was diagnosed in 57 patients, whereas 29 had chronic and 44 acute aortic dissection. In 67 instances a partial and in 35 instances a total arch replacement was performed. The distal arch was approached through a left thoracotomy in 14 patients. Local interventions (n = 17) included surgical reconstruction and glue procedures. Additionally, 55 patients required aortic valve replacement, preferably with composite grafts (n = 46), whereas the valve was reconstructed in 14. Procedures were performed using hypothermia (nasopharyngeal temperature, 11 degrees to 25 degrees C) and circulatory arrest (mean time, 27 minutes). Early mortality was 13.9% at the first operation on the aortic arch. Early deaths included 7 of 57 patients with aortic aneurysm (12.3%), 2 of 29 patients with chronic dissection (6.9%), and 9 of 44 patients with acute dissection (20.5%). Neurological (n = 6) and cardiac events (n = 5) were the most common causes of early death. Since 1987, 7 of 88 patients have died for an overall mortality of 8.0%. With growing experience, proper indication, and adequate operative strategy including the use of circulatory arrest in hypothermia, operation on the aortic arch can be performed with an acceptable risk.

Tactics and techniques of aortic arch replacement.

Operations on the nondissected and dissected aortic arch still pose challenges in terms of the need for and extent of aortic replacement. Our approaches to these lesions are described against the background of 204 operations (58 aneurysms, 54 chronic dissections, and 92 acute dissections), in terms of cerebral protection, procedural choices, and operative technique. Arch anastomoses sparing the supraaortic vessels had shorter periods of circulatory arrest (17.2 min) when compared to tubular arch replacement, with insertion of some or all of these vessels (33.7 min). Early death rates due to cerebral complications were lowest in acute dissections (3/14 fatalities, with two patients showing preoperative cerebral compromise). Based on our experience, we recommend doing subtotal or total arch repiacement in aneurysms regardless of cause. Radical arch surgery should be avoided in acute dissections whenever feasible. instead, the arch should be explored and a blood‐tight distal anastomosis made, going beyond any entry tears encountered in that aortic portion. (J Card Surg 1994;9:538–547)

Decreased incidence of bronchial complications following lung transplantation.

Despite omental wrap and avoidance of prophylactic administration of corticosteroids in the early postoperative phase, ischemic bronchial complications still represent an important source of early morbidity and mortality following lung transplantation. In a retrospective analysis, the effect of pharmacological enhancement of pulmonary collateral flow on bronchial healing was investigated. Thirty-nine consecutive unilateral or bilateral transplant procedures (Tx) were analyzed. Immunosuppression consisted of rabbit antithymocyte globulin (RATG), cyclosporine A, and azathioprine. In group 1 (10 Tx, 12 anastomoses) routine immunosuppression was employed and the anastomoses wrapped with an omental or pericardial pedicle. In group 2 (29 Tx, 41 anastomoses) PGI2 (4 ng/kg per min x 48 h), heparin (200 U/kg per day), and prednisolone (0.5 mg/kg per day) were added to the therapeutic regimen. The 2 groups were comparable with respect to age and sex of the patients, primary diagnosis, type of transplant, intraoperative use of extracorporeal circulation, graft ischemia, duration of mechanical ventilation, and mortality. Bronchoscopic evidence of a significant bronchial ischemia (extending more than 1 cartilaginous ring beyond the anastomosis) was seen in 8 of 12 anastomoses in group 1 vs 14 of 53 anastomoses in group 2 (P = NS). In group 1, significant bronchial stenosis required implantation of an endobronchial silicone stent in 6 of 12 anastomoses, whereas in group 2, no significant bronchial stenosis occurred (P less than 0.01). No negative effects possibly related to the prophylactic administration of corticosteroids could be observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Malperfusion of the Thoracoabdominal Vasculature in Aortic Dissection

Ischemic damage to vital organs supplied by the thoracoabdominal aorta greatly increases the overall risk of aortic dissection. Of 320 patients operated upon for aortic dissection since 1985, 33 (10.3%) underwent operations directed at the relief of malperfusion (15/158 acute type A; 9/18 acute type B; 4/78 chronic type A; 5/66 chronic type B). Organs affected were the kidneys in 32; the bowel in 20; and the spinal cord in 1, while critical lower extremity ischemia was present in 11 patients. In total, 64 vascular areas were affected. Fenestration of the dissecting membrane with or without infrarenal grafting was the procedure performed most frequently in 25, followed by replacement of the descending or thoracoabdominal aorta in 6, and bypass grafting or dlrect revascularization of individual side branches in 6. Six other operations targeted at the affected organs were done. Twenty‐four patients underwent one‐stage operation for malperfusion; in 11, early reoperation after primary aortic repair was necessary, while 2 patients were operated electively. Ten of 33 patients died in hospital, 7 of malperfusion‐induced complications. Of three late deaths, one was related to sequelae of malperfusion. We conclude that Immediate diagnosis and prompt relief of malperfusion offer the best prospects for patient survival. Membrane fenestration appears to be the method of choice for treating malperfusion in most patients, and must be directed to the level of aortic and/or side branch obstruction. (J Card Surg 1994;9:748–757)

Surgical treatment of airway complications after lung transplantation

The treatment of dehiscence or stenosis of the bronchus after lung transplantation has to date consisted of endobronchial stenting or balloon dilation. Operative intervention has been limited to retransplantation with all its limitations. In our series of 121 anastomoses at risk, severe bronchial stenosis occurred in 11 (9%). In five instances the airway complications were treated surgically: two patients underwent retransplantation, one patient had a bilobectomy, and two required sleeve resection of the stenotic segment. All these procedures successfully removed the stenosis. This experience demonstrates that options other than bronchial anastomotic stenting and dilation may be successfully used to overcome posttransplantation anastomotic complications. Conventional resections may result in superior long-term graft function compared with retransplantation, avoiding the immunologically adverse effects of the latter procedure.

Left ventricular function, tricuspid incompetence, and incidence of coronary artery disease late after orthotopic heart transplantation.

Functional results and data concerning the incidence and severity of graft atherosclerosis (GASC) and tricuspid incompetence (TI) in the intermediate term after orthotopic heart transplantation (HTX) are still striking. We examined 92 patients 1, 2, and 3 years after HTX by right and left heart catheterization in order to evaluate pump function, the status of the coronary arteries and the extend of TI, using a double indicator thermodilation technique. Mean left ventricular volumes and ejection fraction were normal 1 and 2 years post-transplant. The incidence of GASC was 8/87 (9.2%) at 1, and 11/92 (12%) at 2 years. It was more frequent (16%) in patients with preexisting coronary artery disease (IHD) than in patients with underlying dilative cardiomyopathy (DCM) (11%). At the end of the 1st postoperative year, 62% of patients were free of TI, whereas only 38% had normal valve function 2 years posttransplant. In 9/14 (64%) of patients, consecutively assessed at 1 and 2 years, TI had increased between both investigations. Preoperative haemodynamics, the number of endomyocardial biopsies and rejection episodes as well as preoperative cardiac size did not correlate with TI. Left ventricular volumes and ejection fraction are normal in the intermediate term after HTX. The incidence of GASC was less than 10% at 1 year and did not significantly increase thereafter. TI is a frequent and yet unexplained finding after HTX showing a considerable tendency to increase with time, but with little or not haemodynamic consequence.

Surgical alternatives in the treatment of life-threatening ventricular arrhythmias

We present our experience in the treatment of life-threatening ventricular tachycardia using electrophysiologically guided surgery (97 patients), automatic implantable cardioverter defibrillator (AICD) (42 patients), and orthotopic heart transplantation (15 patients). Eighty-three percent of these patients had ischemic and 17%, nonischemic heart disease. Our results of electrophysiologically directed surgery show an early mortality of 10% and a recurrence of 5% in the ischemic group. In the nonischemic group, the recurrence was 45%. The AICD was implanted in 31 patients with ischemic heart disease, in 5 with ventricular dysplasia, and in 6 with dilative cardiomyopathy, the ejection fractions ranging from 12% to 65%, with a mean of 30%. Early and late mortalities were 5% and 19%, respectively. The AICD was effective in all patients. Survival rate at 1 year was 83% +/- 6.4%. Thirteen of 15 patients have survived heart transplantation for 3-20 months (mean: 11 months). Ejection fractions prior to transplantation ranged from less than 10% to 34% (mean: 16%). We conclude that electrophysiologically guided surgery is highly effective in most cases of ischemia-related ventricular tachycardia. The AICD is considered a palliative alternative in patients with either poor ventricular function, no electrophysiological substrate, or multimorphological tachycardia. Heart transplantation has to be considered especially in young patients in whom progression of the underlying disease can be anticipated. Bridging by AICD is possible when transplantation is not immediately available or recommendable.