K Ergüne?, T Gökto?an, H Ya?a, U Yetkin, S Bayrak, B Pamuk, N Karahan, A Gürbüz
abdominal aortic aneurysm, morbidity and mortality, risk factors, surgical treatment
K Ergüne?, T Gökto?an, H Ya?a, U Yetkin, S Bayrak, B Pamuk, N Karahan, A Gürbüz. Surgical Treatment Of İnfrarenal Abdominal Aortic Aneurysms: Clinical Trials And Experiences. The Internet Journal of Thoracic and Cardiovascular Surgery. 2007 Volume 11 Number 2.
Background: Despite the fact that stent grafting has been presently in increasing use in the repair of abdominal aortic aneurysm (AAA) with endovascular approach, our aim is to further indicate that traditional surgical correction is a safe method.
Methods: A total number of 66 patients were operated for the infrarenal AAA in our clinic between March 2001 and November 2007. 45 patient underwent elective operation. Urgent procedures were necessary for 21 patients because of ruptured aneurysms. The mean age of patients were 64.65±9.03 (range,36 to 84). There were 64 men and two women. Computed tomography (CT) and abdominal ultrasonography were performed in all patients and 68% of the patients underwent coronary angiography.
Results: Risk factors included smoking (%63.6), coronary artery disease (CAD) (63.6%), hypertension (53%), hyperlipidemia (12.1%), chronic obstructive pulmonary disease (COPD) (9.1%), diabetes mellitus (4.6%), renal dysfunction (serum creatinine level≥2mg/dL) (3%), peripheric arterial disease (18.5%) and carotid artery disease (1.5%). Of the 42 patients with CAD, we performed coronary artery bypass grafting (CABG) to 20 (47.6%) patients prior to AAA surgery and to one patient intraoperatively and percutaneous transluminal coronary angioplasty (PTCA) to 3 (7%) patients prior to AAA surgery. The mean aneurysm diameter was 7.14±1.53 cm (range,5 to 11 cm) with CT scaning. Repair of the AAA was performed with bifurcated aortobiiliac grafts in 33 patients (50%), bifurcated aortobifemoral grafts in 18 patients (27.2%), bifurcated aortoiliac/femoral grafts in 5 patients (7.5%), and aorto-aortic tube grafts in 10 patients (15.2%). Postoperative mortality rate was 12.1%; it was 4.4% in elective AAA group and 28% in ruptured AAA group. The mean follow-up period was 44.97±20.42 months ( range, 2 to 79 months).
Conclusion: This study shows that elective operation for infrarenal nonruptured AAA can be performed safely and with high success rate.
The first succesful surgical treatment of the abdominal aortic aneurysm (AAA) was performed by Dubost, Alay, and Oeconomos in 1951 1. Decline in rates of morbidity and mortality improved increasingly from this dating. This improve is related to improvements in the treatment of coexisting diseases as coronary artery disease (CAD), hypertension, hyperlipidemia, chronic obstructive pulmonary disease (COPD), renal insufficiency, and diabetes mellitus and further it is related to advancements in anesthetic management, in surgical techniques and in experience, in graft materials those were used, and perioperative care 2.
Parodi, Palmaz and Barone showed that repair of AAA with endovascular stent grafting was alternative to the surgical repair in 1991 3. However, sufficient publications about effect to morbidity and mortality in long-term of endovascular repair are not available yet.
In this study we retrospectively showed our experiences and results related to patients who had been performed surgical treatment due to AAA in our clinic.
Patients and methods
Sixty-six patients who had infrarenal AAA were operated in our clinic between the dates March, 2001 and November, 2007. Demographic differentiations, coexisting diseases preoperatively, operative details, and postoperative results were obtained from examination of files of the patients. Survey datas were obtained with hospital office visit of the patients or by telephone interview.
Sixty-four patients were male and two patients were female. Their ages ranged from 36 to 84 years (mean was 64.65±9.03). AAA was nonrupture in 45 patients and they were operated electively. 21 patients who had ruptured AAA was operated emergently.
All patients were evaluated with history of the patients, physical examination, counting complet blood, routine biochemical examination, electrocardiography (ECG), thoracic roentgenography, Doppler ultrasound examination of two lower extremities, and contrast-enhanced computed tomographic scan (CT). Coronary angiography was performed in all of the patients undergoing elective operation.
If patients had recent abdominal pain, shock or hypotension (systolic blood pressure<80 mmHg), decrease hematocrit, retroperitoneal heamatom in CT or surgical intervention, free blood in the retroperitoneum, and fistulization to the next structures we considered that these patients had ruptured AAA.
63.6% (42) the patients were detected to have CAD, 53% (35) hypertension, hypotension 6 (9%), 12.1% (8) hyperlipidemia, 9.1% (6) COPD, 3% (2) renal disfunction, (4.6%) (3) diabetes mellitus, 12 (18.5%) peripheric arterial disease and 1 (1.5%) carotid artery disease preoperatively. Preoperatively mean hematocrit value was 41.89±1.01 (ranged from 39.1 to 44.1) in the patients with nonrupture AAA. Preoperatively mean hematocrit value was 32.35±1.60 (ranged from 30.1 to 36.4) in the patients with rupture AAA (Table 1).
Stenosis over 50% in the coronary arteries were considered as a significant disease and these patients were performed coronary artery bypass grafting (CABG) or percutaneous transluminal coronary angioplasty (PTCA) before repair of AAA.
The patients who had nonsignificant coronary artery stenosis were operated as their medical treatments were ordered. Twenty (47.6%) of 42 patients (63.6%) who had CAD were performed CABG prior to AAA surgery, in one patient simultaneously with AAA surgery CABG has been performed and PTCA was performed prior to AAA surgery in 3 (7%) patients. The mean aneurysm size was 7.14±1.53 cm in all patients. This size was 6.51±1.16 in the patients who underwent elective operation, and 8.47±1.38 cm in the patients who had operated due to ruptured AAA (Table 1).
Repair AAA carried out with a midline transperitoneal incision. Manipulation of aneurysm was avoided before intravenous heparin administration and proximal and distal aortic cross-clamping application, because atherothrombotic debris might cause distal embolization. The distal clamp was applied prior to the proximal clamp. A proximal clamp was placed to region between aortic aneurysm and renal arteries. The stump of inferior mesenteric artery (IMA) was oversewn in the patients who had pressure of mesenteric arteria 40 mmHg or above. The IMA was anastomosed to aortic graft in the patients who had the stump pressure below 40 mmHg. Back bleeding from the loumbar arteries were stopped with matrix sutures. The proximal anastomosis was performed by means of sutures supported with teflon felt in cases that proximal aortic wall was fragile.
Collagen-impregnated polyester fiber vascular graft was used in the patients.
Red blood cell saver device was used to reduce ischemic complications owing to blood loss, the need for transfussion and complications related to blood loss in 21 patients (32%) who had ruptured AAA.
The pearson Chi-Square test and Fisher's Exact test were used to compare the parameters measured in the level of enumarete and classification and Mann-Whitney U test was used to compare the parameters measured in the level of rating between non-rupture and rupture AAA. All analises made with confidence 95% in the program package Windows statistic. Values of p<0.05 were considered statistically significant.
There were no operative deaths. Postoperative mortality occured 8 (12.1%) of the 66 patients and mortality rate was 4.4% (2) in the patients who had operated due to nonrupture AAA, 28% (6) in the patients who had operated due to rupture AAA (p<0.05). The first of 2 patients was operated due to non-ruptured AAA and this patient had CAD, hypertension, and COPD preoperatively and death of this patient was related to cardiac and pulmonary complications in the second postoperative days. The second patient had CAD, hypertension, and peripheric arterial disease preoperatively and he had no indication for CABG or PTCA and he died due to cardiac complication in the second postoperative days.
The first of four patients who died due to ruptured AAA had CAD, COPD, decrease hematocrit value and peripheric arterial disease preoperatively. The second and third patients had CAD, hypertension, decrease hematocrit value and COPD and they died because of cardiac, pulmonary and renal complications. The fourth and fifth patients had CAD, decrease hematocrit value and he died because of cardiac complication. The sixth, seventh and eighth patients had CAD, hypertension, decrease hematocrit value and this patient was performed CABG three years ago and he died because of cardiac complications. Cardiac complications were related to arrhythmias, myocardial failure and myocardial infaction.
The mean age of patients who had non-ruptured AAA was 64.07±7.75, The mean age was 65.90±11.43 in patients who had ruptured AAA. CAD was in 28 (62.2%) of 45 patients who had non-rupture AAA. CAD was found in 14 (%66.7) of 21 patients who operated due to ruptured AAA positive electrocardiographic findings and angina history. We performed no angiography in the patients who had ruptured AAA and were unstable hemodinamically and these patients were operated according to results of CT. Four of patients who had ruptured AAA had performed CABG before AAA repair. We performed aortobiiliac bypass graft to 33 (50%) patients, aortobifemoral bypass graft to 18 (27.2%) patients, aorto-aortic bypass graft to 10 (15.2%) patients, aortoiliac/femoral bypass graft to 5 (7.5%) patients (Table II).
Two patients who had performed aortofemoral bypass graft had femoral artery calcification and these patients were performed endarterectomy. Twelve patients had lower extremity arterial disease preoperatively and the right lower extremity was amputed in the level just below the knee prior to AAA repair in one of these patients.
Nine of 12 patients critically had no ischemic lower extremity findings at time AAA repair and these patients were ordered medical treatment for lower extremity ischemic arterial disease. Three of these patients were performed femoropopliteal bypass grafts due to progression of the underlying disease in the late period.
Mean cross clamp duration was 39.89±5.16 minute in the patients who had non-ruptured AAA and 48.33±5.55 minute in the patients who had ruptured AAA. Mean operation duration was 200.44±15.66 minute in the patients who had non-ruptured AAA and 230.95±16.32 minute in the patients who had ruptured AAA. Durations of cross clamp and operation, and the mean hospitalization time in the patients who ruptured AAA was longer than the patients who had non-ruptured AAA and these findings were meaningful statistically (Table III) (p<0.05).
Operative mean blood loss was 919.05±218.21 cc (ranged from 600 to 1300 cc) in the patients with rupture AAA. Operative blood loss was 353.33±53.72 (range, from 250 to 500 cc) in the patients with nonrupture AAA. Operative mean blood loss was more and statistically significant in patients that we operated due to ruptured AAA when compared to those of the cases with non-ruptured aneurysms (p<0.05).
In all patients the mean hospitalization time was 6.64±1.32 days (4 to 11 days). In the patients who had operated due to non-ruptured AAA the mean hospitalization time was 6.35±1.23 days (4 to 11 days). In the patients who had operated due to ruptured AAA, the mean hospitalization time was 7.47±1.24 days (6 to 10 days).
The most seen postoperative complication was (21.2%) (14 patients) cardiac events (arrhytmias) and arrhythmias improved with medical treatment in eight patients with arrhythmia postoperatively. Eigth patients with rupture AAA had arrhythmia postoperatively. Six of these patients died because of arrhythmia, cardiac failure and pulmonary complications.
Pulmonary complication related to respiratory distress syndrome was seen in the five (9.4%) patients and improved with medical treatment. Preoperatively A dialysis-dependent patient (1.9%) required postoperative dialysis support. In one patient who had operated due to ruptured AAA, there was fistulization to the inferior vena cava (IVC) and IVC was repaired primarly. One patient had conscious disturbance, and paraparesia in the both of lower extremities, conscious disturbance improved in this patient but paraparesia continued (Table IV).
One patient who had performed CABG before AAA repair had gastrointestinal hemorrage in the second postoperative days after AAA operation and the stomach ulcus hemorrage was cotherized and treatment of ulcus was maintained with drugs.
The mean follow-up was 44.97±20.42 (range from 2 to 79 months) months. Control visits of patients were performed physical examination, routine biochemical studies, ECG, thoracic roentgenography, and Doppler ultrasound examination of the lower extremities.
No graft thrombosis and infection had been appeared in follow-up. There wasn't any death in follow-up period. The overall survival rate was 87.9%. This rate was 95.6% in the patients who had operated due to non-ruptured AAA, 72% in the patients who had operated due to ruptured AAA.
As a result of continuous advances in the surgical, anesthetic, and intensive care techniques, the outcome of elective open AAA repair has improved costantly. Elective surgical treatment of AAA can be successfully performed at a 1-5% rate of mortality recent years 2,4,5,6,7.
Decline in rates of morbidity and mortality is associated with early diagnosis, treatment of coexisting diseases prior to AAA surgical procedures, advancements in surgical techniques and experience and improvements in follow-up in the postoperative intensive care unite. Despite all these, early mortality rate was between 29-45% in ruptured aneurysms 8,9.
In our series postoperative mortality rate was 4.4% in cases, which we electively operated due to non-ruptured AAA whereas it was 28% in ruptured AAA cases.These finding were meaningful statistically (p<0.05). Overall mortality rate was 12.1%. This low rate of early mortality in patients who were electively operated showed similarity with that of the previous publications.
CAD is a major risk factor in patients scheduled for surgical treatment of AAA and causes elevated rates of morbidity and mortality.
Apart from Hertzer and colleagues, Roger and colleagues also reported high rates of CAD in AAA patients 10,11.
Hoffman and colleagues displayed CAD to play a substantial role in increasing rate of mortality in cases that underwent surgical treatment of ruptured AAA 12.
In our series, we performed coronary angiography before the AAA repair in all patients who electively underwent operation, and 28 (62.2%) of these patients were detected CAD. We performed CABG to one patient intraoperatively. CABG was performed 17 patients prior to AAA surgery and PTCA were performed 3 patients prior to AAA surgery.
Thus, we performed coronary revascularization on a total of 82.1% (21) of cases which had CAD before elective AAA surgery had not been performed. The other 7 (17.9%) patients who had CAD did not show any indication for coronary revascularization and they received medical treatment before elective AAA surgery had not been performed. Four of patients who had ruptured AAA had performed CABG before AAA repair. No early period mortality was present among CAD patients either with CABG or PTCA, but there were 8 deaths among those ruptured or non-ruptured AAA cases with CAD, which did not undergo coronary revascularization. In addition to a review of a body of literature, considering the low rate of mortality and morbidity outcome in our cases of elective AAA repair, we can say that in patients with AAA and severe coronary lesions, coronary revascularization prior to AAA surgery declines intraoperative ischemic complications and the rate of associated morbidity and mortality.
Preoperative presence of advanced age, serum creatinin level≥2 mg/dL, COPD and peripheric arterial disease have been showed to increase the rate of morbidity and mortality in patients operated for the surgical treatment of AAA 8,13,14,15.
Table I presents data illustrating higher rates of preoperative risk factors such as advanced age, CAD, COPD, periferic arterial disease, creatinin level≥2 mg/dL and hyperlipidemia pertaining to patients, who underwent surgical treatment of AAA.
However, the difference between the risk factors of ruptured and non-ruptured AAA cases did not show statistical significance. Preoperative detection of risk factors and appropriate treatment can reduce postoperative morbidity and mortality rates.
Preoperative pulmonary care and medical treatment, postoperative early extubation and ambulation reduce the risk of pulmonary dysfunction in those patients with COPD. We determined that COPD were important predictor for postoperative death (p<0.05). Moreover, in order to protect kindeys it is important to administer intravenous mannitol and diuretics in patients with a serum creatinin level≥2 mg/dL to maintain as well as to increase the urinary output under appropriate intraoperative hydration.
Erwin and colleagues stated the duration of operation to be effective on postoperative early morbidity and mortality in cases operated for the surgical correction of ruptured AAA 8.
Cross-clamping and operating durations During an AAA operation, in order to avoid potential surgical complications, cross-clampimg and operating durations must be kept to minimum.
Orend and colleagues, Alric and colleagues reported that the use of red blood cell salvage using a cell saver device reduced mortality in ruptured AAA patients 15, 16. Red blood cell saver device was used in patients that we operated due to ruptured AAA. Operative mean blood loss was more and statistically significant in patients that we operated due to ruptured AAA when compared to those of the cases with non-ruptured aneurysms (p<0.05).
Recently, endovascular AAA repairing has been recommended as an alternative to AAA surgery. Endovascular repair has disavantages on its own right like endoleaking, stent migration, device defects and graft femoral occlusion 18,19,20.
Endovascular repair can be recommended for patients who have preoperative high risk factors such as 80 years of age or more, serum creatinin level≥2 mg/dL, pulmonary insufficiency (need for oxygen support at home, forced expiratory volume in 1 second (FEVI) ≤20%, cardiac disfunction (left ventricular ejection fraction (LVEF)<20%, new or recurring congestive heart failure, symptomatic aorta stenosis, CAD that cannot be revascularized with unstable angina, and history of multipl abdominal operation. Endovascular repair lessens blood loss as well as shortening the length of intensive care and hospitalization. However, the influence of endovascular repair on morbidity and mortality in the long term is not known 18,19,20. Conversion from endovascular repair to open AAA repair is last and select treatment method in patients who had complications as endoleak, graft limb occlusion, graft rupture and AAA rupture which present after endovascular repair.
In conclusion; Infrarenal non-ruptured AAA repair can be performed at low rates of morbidity and mortality if patients with associated risk factors such as COPD and renal dysfunction receive an appropriate preoperative and postoperative treatment, and revascularization of associated CAD is performed prior to the surgical treatment of AAA.
Dr.Kazım Ergüneş. 2040-1 Sokak, Selçuk-1, No:2, Daire- 51, Mavişehir. 35540 Karşıyaka-İZMİR / TURKEY Tel: +90232-2444444 Fax: +90232-2434848 E-mail:firstname.lastname@example.org & email@example.com