Mitral valve replacement with glutaraldehyde preserved aortic allografts

OBJECTIVE

To present long-term results after mitral valve replacement with stent mounted glutaraldehyde preserved aortic allografts in patients older than 15 years. The clinical support for this study was to combine the glutaraldehyde technique of biological tissue preservation with the advantages of allografts when compared to xenografts. This was demonstrated in previous studies using other methods of tissue processing.

METHODS

Between September 1984 and November 1994, 70 patients aged 16-77 years (mean 35.4 years) underwent mitral valve replacement with this preserved and mounted allograft. Of these, 40 patients (57.2%) were aged 16-35 years and 15 (21.4%) were 20 years old or younger; 46 (65.7%) were females and 24 (34.3%) males. Single mitral valve replacement was performed in 60 patients and 10 were also subjected to other combined cardiac procedures. Human aortic valves were obtained during routine autopsy, processed in glutaraldehyde and mounted into flexible stents, using the same technique as that used for porcine bioprostheses.

RESULTS

Hospital mortality was 1.4%. Total follow-up was 543.1 patient-years, corresponding to a mean follow-up of 7.9 years per patient. Echocardiography demonstrated a hemodynamic performance similar to porcine bioprostheses. Late mortality was 0.7 +/- 0.6% per patient-year and the causes were congestive heart failure in 2, prosthetic endocarditis in 1 and acute myocardial infarction in 1. The 12-year actuarial survival was 92.4 +/- 3.2%. The incidence of late complications was 5.2 +/- 1.2% per patient-year, including congestive heart failure, prosthetic endocarditis, periprosthetic leak, thromboembolic episodes, recurrence of rheumatic disease, coronary artery disease and allograft failure. Complications related to heart disease represented 2.8 +/- 0.6% and allobioprosthesis-related 2.4 +/- 0.5% per patient-year. The 12-year actuarial freedom from primary valve failure was 81.0 +/- 15.0%. The incidence of reoperations was 1.5 +/- 0.8% per patient-year and the main indication was prosthetic endocarditis. Other causes were periprosthetic leak, aortic insufficiency in the native aortic valve and allobioprosthesis dysfunction. Functional results demonstrated a significant improvement in patients clinical condition.

CONCLUSION

This 12-year follow-up shows a very low incidence of primary allograft failure for patients older than 15 years undergoing mitral valve replacement, and much superior than our results with porcine bioprosthesis in the same age group. This supports our assumption that this investigational valve represents a new advance in cardiac valve surgery.

[Partial atrioventricular septal defect associated with right atrioventricular valve Ebstein's disease]

The association of Ebstein's disease and atrioventricular septal defect is extremely rare with only 13 cases described in the literature and none in our country. We described a 15 year-old girl with echo and angiographic diagnosis confirmed by surgery. The non-identification of one of the lesions could impair planning and surgical results.

Surgical treatment of acute type B aortic dissection using an endoprosthesis (elephant trunk)

BACKGROUND

The surgical treatment of acute complicated type B aortic dissection continues to be a challenge and is still associated with high morbidity and mortality rates.

METHODS

Seventy consecutive patients with an acute type B aortic dissection underwent an elephant trunk procedure through a median sternotomy during deep hypothermic circulatory arrest. An endoprosthesis that was 22 to 24 mm in diameter was inserted through an incision in the arch and held in place with only proximal sutures.

RESULTS

The mean arrest time was 31.4 +/- 8.7 minutes, and it was possible to adequately position the endoluminal graft in every patient. The procedure was done in association with other procedures in 13 patients. There were six in-hospital deaths not related to the endoprosthesis, and four late deaths. Late reoperation was necessary in 6 patients to manage leakage at the proximal suture line.

CONCLUSIONS

The insertion of an endoprosthesis through the arch for the management of a complicated acute type B dissection has several advantages over the conventional thoracotomy approach. The hospital mortality rate in this series of 70 patients was 20%, and the actuarial 5-year survival rate was 62.5%. We consider the elephant trunk procedure the treatment of choice in patients with type B acute dissections, regardless of whether the dissection is complicated or not.

Transaortic approach has a role in the surgical treatment of ventricular septal defects

A transaortic approach was used for surgical closure of ventricular septal defects (VSDs), sometimes as first choice and otherwise as an alternative approach. This paper presents the experience in a group of 124 patients who underwent VSD closure by a transaortic approach in an 18-year-period, between 1974 and 1992. Patients were divided in three groups: (I) Isolated VSD, 89 patients (mean age 7.6 years); (II) VSD associated with other malformations, 27 patients (mean age 10.8 years); and (III) recurrent VSD, eight patients (mean age 15.6 years). Two deaths occurred in the postoperative period (2/124), one after closure of VSD in a patient with severe pulmonary hypertension; another death was observed after transaortic closure of the VSD as part of the repair of a complex heart malformation. There were no instances of new right bundle branch block (RBBB) in the group operated on for isolated VSDs. Three cases of left bundle branch block (LBBB) (3.4%) occurred in the isolated VSD group. There were no cases of complete aortic valve (AV) block in the whole series and no instances of AV dysfunction. The transaortic approach is an alternative for the surgical treatment of ventricular septal defects. The ease of exposure and closure of defects suggest this technique to be a particularly attractive approach in the treatment of small to moderate-sized VSDs and also in recurrent VSDs.

[Myocardial revascularization without extracorporeal circulation. Surgical results in 1090 patients]

PURPOSE

To report our experience of 12 years of myocardial revascularization without cardiopulmonary bypass (CPB) and to discuss its expanding surgical indications.

METHODS

This technique was employed in 1090 patients, between September/81 and April/93, corresponding to 17.4% of all revascularized patients. Regarding gender, male patients were the majority (73.7%) and ages ranged from 28 to 86 year-old (mean 57). Chronic coronary insufficiency was the main indication (69.4%) and 18.9% of our global experience were operated on during acute ischemia. The average number of grafts per patient was 1.6 and internal mammary artery was utilized in 60.1% of patients. Left anterior descending coronary artery and right coronary artery were the coronary arteries most often treated.

RESULTS

Our hospital mortality rate was 2.5% (28/1090) although it was 7% for patients over 70 years. The most common cause of death was cardiogenic shock after failed angioplasty. Postoperative complications included AMI in 4.8%, arrhythmias in 5.5% and pulmonary in 3.2%. Mean of any type of blood derivate utilization was 0.28 units/patients.

CONCLUSION

Myocardial revascularization without CPB is a valid alternative in a selected cohort of patients and it is performed with low morbidity and mortality. Nowadays it represents an excellent tactical option for high-risk patients and in failed angioplasties.

[Late development of congestive heart failure in interventricular communication caused by penetrating wound, with pulmonary hypertension resolution after surgical correction]

Male, 33 years-old, with onset of heart failure and edema; he used to be completely asymptomatic but mentioned he underwent previously a pleural drainage, after a hemothorax provoked by a stab wound. His physical examination confirmed he was in heart failure and showed a harsh holosystolic murmur between mitral and tricuspid areas. Cardiac catheterization demonstrated a large apical ventricular septal defect (VSD) and systemic pulmonary arterial pressures. With oxygen there was an increase in the left to right shunt and normal pulmonary vascular resistance. The clinical diagnosis was that of a traumatic VSD provoking pulmonary hypertension although a congenital etiology could not be completely ruled out. At surgery there was a sharp cut at the pericardium and an apical epicardial lesion; the VSD was patch sutured and the patient did well with control of his heart failure. A control hemodynamic study performed within the first postoperative month showed no residual shunt and complete normalization of the pulmonary pressures and resistance.

[Hemodynamic study with Swan-Ganz catheterization, concomitant to endomyocardial biopsy in heart transplantation patients. Importance in the early diagnosis of rejection]

PURPOSE

To evaluate the role of hemodynamic parameters in the diagnosis of acute rejection who underwent orthotopic cardiac transplantation.

METHODS

A protocol was carried out in 19 patients who underwent heart transplantation and in whom Swan-Ganz hemodynamics was performed immediately prior to routine endomyocardial biopsy in the first few months postoperatively. The results of 28 biopsies were divided in group I--severe rejection who needed pulse-therapy (n = 10) and group II--No or mild/moderate rejection who did not need any pulse (n = 18). Hemodynamic parameters were compared between both groups.

RESULTS

There were significant differences among hemodynamic parameters in groups I and II. Group I had higher mean right atrial pressures (13.0 x 7.3 mmHg), mean pulmonary pressure (26.3 x 20.4 mmHg), mean wedge pressure (14.4 x 10.9 mmHg) and lower cardiac index (2.57 x 3.10 l/min/m2).

CONCLUSION

In a routine situation, hemodynamic measurements, as obtained with Swan-Ganz catheter, simultaneously with endomyocardial biopsies, show significant alterations in transplanted patients who develop acute rejection. This information, obtained earlier than the biopsy results, could shorten the time to initiate pulse-therapy in patients with severe rejection.

[Early and late results of myocardial revascularization after coronary thrombolysis with intravenous streptokinase in the treatment of acute myocardial infarction]

PURPOSE

To study the early and late results of patients treated initially intravenous streptokinase and then with coronary artery bypass surgery.

METHODS

One hundred and twenty one patients with acute myocardial infarction less than 6 hours duration were treated initially with intravenous streptokinase, and 1-38 days after (median 8.80 days) coronary artery bypass was undertaken. Ninety six patients were operated with extracorporeal circulation and 25 without it.

RESULTS

Overall operative mortality was 3.30% (4/121). Reoperations due to bleeding was necessary in 3.30% (4/121). Late mortality was 5.40% with survival probability of 94.60% after 36 months and 92.30% after 70 months. Late morbidity events in terms of angina and cardiac insufficiency demonstrated that 7 patients had angina, 4 cardiac insufficiency and two angina and cardiac insufficiency; probability to be free from these events was 88.20% after 46 months and 66.40% after 70 months.

CONCLUSION

Coronary artery bypass surgery after intravenous streptokinase can be undertaken with security and excellent early and late results.

[Systemic-pulmonary shunts in congenital heart diseases with decreased pulmonary blood flow: critical analysis of the surgical techniques and immediate results]

PURPOSE

To evaluate immediate postoperative results in children with congenital heart disease and decreased pulmonary blood flow who underwent a systemic to pulmonary shunt.

PATIENTS AND METHODS

Sixty-four patients underwent surgery, 46.8% (30) of them males with ages from 1 day to 17 years old. They were divided in three groups: I--13 pts (20.3%) who underwent classical Blalock-Taussig (BT) shunt; II--46 pts (71.8%) who underwent modified BT shunts, 34 of them with polytetrafluoroetylene (PTFE) and 12 of them with umbilical vein shunts; III--5 pts (7.8%) with central anastomosis that were made with three different types of graft; 3 PTFE, umbilical vein and bovine mammary artery in one each. The simultaneous procedures were: section and suture of PDA--2, closure of systemic-pulmonary collaterals--3, pulmonary valvotomy--3, right ventricular outflow patch--3, pulmonary branch stenosis (enlargement)--2.

RESULTS

In group I there were 4 (30.7%) closures, with two immediate reoperation and a total mortality of 30.7%. In group II there were 4 closures (8.6%) and two reoperations with a mortality of 15.2% (7 cases). In group III there was one graft closure and an overall mortality of 80% (4 pts). When analysing deaths due to the shunt itself the mortality rate was respectively 15.3%, 8.6% and 40.0%.

CONCLUSION

Modified BT operation was performed most frequently in our service; it was associated with less closure and mortality than the other types of shunt. It is considered our first alternative for a systemic-pulmonary shunt.

Cardiac valve replacement with glutaraldehyde preserved aortic allografts

From September 1984 to December 1988, 144 patients underwent cardiac valve replacement using glutaraldehyde preserved stent mounted aortic allografts. The mean age was 21.4 years (54.9% were 15 years old or younger). The mitral valve was replaced in 125 patients, the aortic valve in 7, the pulmonary valve in 3, the tricuspid in 1, the mitral and tricuspid in 1, and the aortic and mitral in 7. Hospital mortality was 2.8% (4 patients). Total follow-up was 396.3 patient-years and the mean follow-up was 2.8 years per patient. The 5-year actuarial survival was 73.8% +/- 11.9%. The 4-year actuarial survival for patients aged 15 or younger was 81.4% +/- 7.1%. The overall mortality was 2.8% +/- 0.8%/per patient-year. The incidence of valve-related complications was 4.8% +/- 1.1%/per patient-year, and the calcification rate was 3.0% +/- 0.9%/per patient-year and was the main complication reported in 12 patients, all under the age of 15 years. It occurred 14-47 months after implantation (mean 32.7 months). Five-year actuarial freedom from valve dysfunction due to calcification was 82.6% +/- 5.0% and for patients aged 15 or younger was 69.9% +/- 8.8%. The incidence of reoperation was 3.3% +/- 0.9%/per patient-year. These initial results demonstrate a 5-year actuarial freedom from primary valve failure due to fibrocalcification superior to the results obtained with xenobioprostheses in the paediatric age group.

Myocardial revascularization without extracorporeal circulation. Seven-year experience in 593 cases

The authors present the results of 593 consecutive and non-selected patients who underwent direct myocardial revascularization without extracorporeal circulation in the period September 1981 to December 1988. The results are compared with 3086 patients who underwent conventional bypass surgery over the same period of time. The ages varied from 33 to 80 years (mean = 56) with 40 patients older than 70. The overall mortality in the group without cardiopulmonary bypass (CPB) was 1.7% (10/593) compared with 3.8% for conventional revascularization. Our mortality in the last 3 years has been 0.5% and 0% in the last 203 patients revascularized without CPB. The number of grafts varied from 1 to 5 (average 1.6). The treated arteries were: anterior descending (557), right (282) marginal (5) and circumflex marginal (4). Immediate postoperative complications were fewer and hospital discharge was earlier in the group treated without CPB. The authors conclude that this tactical alternative has the advantages of: lower morbidity and mortality, lower cost and no need for blood transfusion. Drawbacks are the need for greater technical expertise and it seems to be possible in about 19% of all patients who undergo myocardial revascularization.

Serum ferritin and hemochromatosis alleles in chronic hemodialysis patients

There have been some reports on the risk of developing hemosiderosis in hemodialysis patients when heavily transfused and simultaneously possessing hemochromatosis alleles (HA). We evaluated 99 patients on chronic hemodialysis estimating their serum ferritin (SF) levels, transfusion rate, and prevalence of HLA A3, B7 and B14 alleles, which are considered to be more frequent in idiopathic hemochromatosis. We analyzed the patients as a whole group and also separately as low or high transfusion groups. There was no correlation between the number of HA and the mean SF levels. The presence of HA is not a risk factor for the development of hemosiderosis when excessive transfusions and parenteral iron administration are avoided.

Modified Blalock-Taussig shunt with an umbilical vein graft

We describe a modification of the Blalock Taussig anastomosis, with the interposition of a glutaraldehyde-tanned umbilical vein graft between the subclavian and pulmonary arteries. This operation was performed in 64 children: 11 were less than 1 month of age (17.2%), and 23 were between 1 and 6 months of age (34.9%). Hospital deaths occurred in six patients-all less than 6 months of age (9.4%). There was no instance of shunt occlusion noted. The clinical course was uneventful among survivors, except for one patient who died of endocarditis in the late postoperative follow-up. The shunt procedure may be performed very rapidly, with minimal dissection, allowing the use of a graft larger than the diameter of the subclavian artery. This modification of the Blalock Taussig operation compares favorably with our previous experience with other shunt procedures and may be considered a valuable alternative in the palliative surgical treatment of several malformations with severe pulmonary oligemia.

Direct myocardial revascularization without extracorporeal circulation: technique and initial results

In a 10-month period, 68 patients underwent saphenous vein bypass revascularization without extracorporeal circulation. Distal sutures were performed with interruption of coronary flow without any devices for perfusion of the coronary artery; the proximal sutures were completed with tangential clamping of the aorta. Most frequently, the anterior descending and the distal right coronary arteries were revascularized; of 225 patients who underwent bypass surgery, this technique was possible in 68 cases (30.2%). The 30-day hospital mortality was 1.5%, and perioperative myocardial infarction, as determined by daily electrocardiograms (ECGs) and creatine phosphokinase isoenzyme (CKMB), occurred in two patients. Control hemodynamic studies were performed in 22 of the 68 patients (32.4%) with a patency rate of 84.2% in the grafts restudied.

Direct myocardial revascularization without cardiopulmonary bypass

The authors present their experience with 160 patients who underwent coronary artery saphenous vein bypass revascularization without cardiopulmonary bypass. The distal sutures were performed with interruption of the coronary flow without any devices for perfusion of the coronary artery: the proximal sutures were made with tangential clamping of the aorta. Vessels most frequently revascularized were the anterior descending and the distal right coronary artery. Out of 597 patients who underwent bypass surgery in this period, this technique could be employed in 160 cases (26.8%). Hospital mortality was 3.1% (5/160) and perioperative myocardial infarction as determined by daily EKGs and CKMB occurred in 4 patients (2.5%). Control hemodynamic studies were performed in 41 of the 160 patients (25.6%) with a patency rate of 83.9% in the 62 grafts restudied. We conclude that direct myocardial revascularization can be performed safely without major difficulties and with efficient anastomoses. The main advantages of the technique are that it does not require the use of extracorporeal circulation and, consequently, the use of any blood, as well as its low cost due to shorter hospitalization periods.

Surgical treatment of endomyocardial fibrosis

Thirty patients with endomyocardial fibrosis were submitted to endocardial decortication and atrioventricular valve replacement between December, 1977, and October, 1981. There were 26 female and four male patients, ranging in age from 14 to 48 years (mean 32). Thirteen patients had biventricular disease, 14 had the right-sided form, and three had endomyocardial fibrosis confined to the left ventricle. All were in Functional Class III or IV (New York Heart Association classification). The hospital mortality was 20% (six cases). Among the survivors (mean follow-up 13 months), 23 of 24 were improved clinically. Postoperative hemodynamic and angiographic studies were performed in 15 patients. Two (6.6%) have definitive atrioventricular heart block. There were five (16.6%) late deaths. Operation for endomyocardial fibrosis should be considered a palliative procedure. Possible limitations include the need for a valve prosthesis, cardiac conduction disturbances secondary to endocardiectomy of the right ventricle, and the possibility of recurrence of the endocardial fibrosis. However, at present, operation seems to be the treatment of choice for this condition because (1) endomyocardial fibrosis is characterized by a grave prognosis and medical therapy is ineffective; (2) endomyocardial fibrosis is a disease in which only the heart is affected, lesions in other organs being the result of passive congestion; (3) systolic performance of the heart is usually only slightly depressed; and (4) the surgical procedure is easily performed, so that the mortality is acceptable.