Table of Contents  
ORIGINAL ARTICLE
Year : 2022  |  Volume : 9  |  Issue : 2  |  Page : 163-169

Contemporary portrait of aortic bifurcated bypass procedures for occlusive disease in indian population: A transition in trends


1 Department of Vascular Surgery, CMC, Vellore, Tamil Nadu, India
2 Department of Vascular Surgery, Sultan Qaboos University Hospital, Seeb, Oman

Date of Submission16-Nov-2021
Date of Acceptance30-Dec-2021
Date of Web Publication13-Jun-2022

Correspondence Address:
Prajna B Kota
Department of Vascular Surgery, CMC, Vellore, Tamil Nadu
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijves.ijves_120_21

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  Abstract 


Purpose: We sought to scrutinize the current clinical profiles and postoperative outcomes, following aortic bifurcated bypass (ABB) for occlusive arterial disease, over the past ten years and compare them with our formerly published dataset. Methods: From January 2011 to December 2020, a prospective single hospital database was maintained for ABB procedures in patients with occlusive disease. Clinico-demographic profile and postoperative outcomes were surveyed and assessed for associations. Graft patency, amputation-free survival, and mortality were the primary end points. In addition, we did a comparison analysis with our historical cohort to appraise the shift in trends. Results: Over the past ten years, 140 patients (mean age of 54.5 years) underwent ABB procedures for aortoiliac occlusive disease (AIOD). Majority were males (94.3%) with chronic limb-threatening ischemia (88.6%). Atherosclerosis was the most common etiology (85.7%). There was a significant increase in smoking (P < 0.001), dyslipidemia (P < 0.001), coronary artery disease (P < 0.001), chronic kidney disease (P = 0.05), flow limiting infra-inguinal disease (P < 0.001), intermediate graft thrombosis and primary amputation rates in the contemporary cohort (P = 0.050). No significant changes were noted in the 30-day mortality rates. The contemporary primary patency rate is 76.9%, and secondary patency rate is 94.2%, compared to an overall patency of 84% in the historical cohort. Conclusion: Our study highlighted the epidemiological shift transpiring in patients affected by AIOD in India. Despite challenging clinical profiles, our outcomes remain unchanged and are comparable to western literature.

Keywords: Aorto-bifemoral bypass, aortobifurcated bypass, aorto-iliac occlusive disease, graft patency


How to cite this article:
Kota PB, Kota AA, Samuel V, Premkumar P, Selvaraj D, Stephen E, Agarwal S. Contemporary portrait of aortic bifurcated bypass procedures for occlusive disease in indian population: A transition in trends. Indian J Vasc Endovasc Surg 2022;9:163-9

How to cite this URL:
Kota PB, Kota AA, Samuel V, Premkumar P, Selvaraj D, Stephen E, Agarwal S. Contemporary portrait of aortic bifurcated bypass procedures for occlusive disease in indian population: A transition in trends. Indian J Vasc Endovasc Surg [serial online] 2022 [cited 2022 Jul 3];9:163-9. Available from: https://www.indjvascsurg.org/text.asp?2022/9/2/163/347252




  Introduction Top


Across studies, the prevalence of peripheral arterial disease ranges from 3.6% to 19%.[1] South Asians are known to have a less favorable vascular risk factor profile, in contrast to Caucasians.[2] Shead et al.[3] found aorto-iliac occlusive disease (AIOD) to be the third most commonly involved segment among Indians. In 1955, Cockett performed the first aortic bypass surgery for occlusive disease.[4] Despite quantum leaps in endovascular reconstruction, aortic bifurcated bypass (ABB) procedures remain the standard of care for advanced AIOD. In this study, we reviewed our experience with ABB procedures and appraised the transition of trends in the Indian population.


  Methods Top


Patients and definitions

Following approval by our Institutional review board, consecutive patients with AIOD, who underwent ABB procedures between January 2011 and December 2020 at our center were identified through a prospectively maintained database and included in this study. We have included elective as well as emergency operations and both aorto-iliac/aorto-femoral configurations in the study. Demographic data, clinical presentations, comorbidities, operative details, complications, hospital stay, mortality, and readmissions were recorded. Clinical follow-up was irregular, and patients who could not attend the hospital were assessed on a telephonic basis. The diagnosis was based on clinical examination, ancillary tests such as Ankle Brachial Pressure Index, toe pressures, imaging modalities such as computed tomography angiography (CTA) or magnetic resonance angiography (MRA) (in patients with renal dysfunction) and biochemical tests (for etiological diagnosis). Patients were offered surgery, if they had disabling claudication or chronic limb-threatening ischemia (CLTI). All patients were counseled regarding abstaining from tobacco, lifestyle modifications, and received the best medical management (including low dose aspirin, low to moderate-dose statins, glycemic control measures, antihypertensives, and cardiac medications). In all surgeries, synthetic grafts, either Dacron or Expanded Poly-tetrafluoro ethylene (ePTFE) were used, matched to the size of the native arteries. The definitions of postoperative morbidity were based on the reporting standards for lower limb ischemia by Rutherford et al.[5] Graft patency was defined by clinical examination followed by imaging confirmation (Duplex ultrasound, CTA, or MRA). Failed grafts were defined as early graft thrombosis (thrombosis occurring within 30 days of operation), intermediate graft thrombosis (thrombosis from 30 days to 2 years), and late graft thrombosis (failure after 2 years). Primary amputation was defined as amputation simultaneously performed at index operation, and secondary amputation was defined as amputation performed following revascularization, either during the same hospitalization or at follow-up. All amputations below the ankle joint were defined as minor amputations, and those above the ankle joint were termed as major amputations.

End points

Primary end points included graft patency, amputation-free survival and 30 day mortality rates. Secondary end points included the complication profile and its association with demography, clinical presentation, and operative technique. A comparison analysis with our previously published dataset was carried out to observe the shift in trends.

Statistics

Summary statistics such as Mean and Standard Deviation were presented for all continuous variables, and absolute number and percentage were presented for categorical variables. The Chi-square test and Fisher exact test were used to find the association of demographical and clinical parameters with outcome. Outcome analysis was done with the Kaplan-Meier method to determine the survival probability. t-test and proportion test were used to compare the parameters in two study time periods. The significance level 0.05 was considered as statistically significant. SPSS IBM version 23 (Armonk, NY : IBM Corp) was used to perform the statistical analysis.


  Results Top


Contemporary Perspective: From January 2011 to December 2020, 140 patients underwent ABB graft procedures for AIOD [Table 1]. One hundred and thirty two patients (94.3%) were male and 8 (5.7%) were female. The mean age was 54.51 ± 9.67 years, ranging from 25 to 77 years. Most of the patients had CLTI (88. 6%). The mean time to presentation was 17.6 months (15 days-96 months) from the onset of symptoms. Later presentations were seen to be associated with a higher incidence of lymph leaks, groin infections, chance of reactionary hemorrhage, and primary amputations. Atherosclerosis was the predominant aetiology in 120 patients (85.7%), whereas 18 (12.9%) had thromboangiitis obliterans and two had other aetiologies (one large vessel vasculitis and one probable prothrombotic etiology). 97.1% patients had a history of significant smoking. The mean hospital stay was 14.9 days (range: 6–45 days).
Table 1: Clinico-demographic distribution

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Six patients (4.3%) succumbed within 30 days of operation. Four died during their hospital stay and two after discharge. The primary cause of mortality was surgical in two patients and medical in four. Graft infection with graft blowout and mesenteric ischemia leading to multiorgan dysfunction, despite operative intervention, constituted the surgical causes. Massive postoperative myocardial infarction (MI) led to early mortality in the other four patients. When we looked at the univariate analysis of clinic-demographic predictors and operative aspects in relation to 30-day mortality, we found no significant predictors.

Late mortality was known through telephonic interviews. Of those available, nine patients had passed away, one of whom was attributable to late thrombosis of the graft. Of the rest, five had an MI, one had a lung malignancy, and one succumbed to a motor vehicle accident.

Of the nine patients (6.4%) who had a postoperative cardiac event and two had been identified to have preexisting cardiac disease (based on symptoms, electrocardiography (ECG), and echocardiogram). In four patients, the cardiac event proved fatal. Among the rest, two required intensive care with noninvasive ventilation and all were managed conservatively with therapeutic anticoagulation. On univariate analysis, we found a past history of cerebrovascular accident (CVA) and dyslipidemia to be significant predictors of perioperative MI.

Postoperative pneumonia was the most common medical complication following surgery (11 patients, 7.9%). Pneumonia lead to mortality in two of these patients. Among the rest, six required prolonged ventilatory support, while the others were managed with antibiotics and physiotherapy. On univariate analysis, past history of CVA was a significant predictor toward developing pulmonary complications.

Colonic ischemia was seen in two patients (1.4%). One patient had concomitant aorto-superior mesenteric artery (SMA) bypass with acute graft thrombosis, for which an emergency SMA thrombectomy, jejunal resection, and feeding jejunostomy was done. The other developed, acute inferior mesenteric artery (IMA) thrombus, underwent IMA thrombectomy followed by sigmoid resection and Hartman's procedure and ultimately succumbed to ventilator associated pneumonia. Because of the low incidence of this complication, we are unable to comment on predictors.

Postoperative renal dysfunction was seen in two patients, of which one was transient, whereas the other was dialysis-dependent acute kidney injury, which contributed to early mortality. Two patients had ischemic strokes in the immediate postoperative period, which were managed conservatively on anticoagulation, with no residual neurological deficits. Because of the low incidence of these complications, we are unable to comment on predictors.

Hemorrhagic complications were seen in seven patients (5%). Three had retroperitoneal hemorrhage, of which one required emergency laparotomy, and the other two were managed conservatively with blood product support. Two patients had graft infection and secondary blow-outs one underwent emergency debridement and explant, while the other had uncontrollable bleeding and succumbed in the ward. One patient had a fatal bleed from a distal bypass site (Sequential bypass from graft to posterior tibial artery). One patient had a subcutaneous groin hematoma, which was managed conservatively. On univariate analysis, the presence of chronic kidney disease (CKD) and prior history of CVA were significant predictors of bleeding.

When looking at local groin complications, seven patients had seromas post-procedure. All of these were unilateral (two on the right and five on the left). Two of the seromas were aspirated under sterile conditions, and the rest were managed conservatively. Lymph leak was the most common surgical complication ,seen in 18 (12.9%) patients. Five had bilateral lymph leaks, and seven had unilateral leaks. One required surgical re-exploration for control of the lymph leak, and others were managed conservatively with sterile talc and/or tetracycline powder and frequent dressing change. There were no significant predictors for seroma formation and lymph leak.

Groin infection was seen in 9 (6.4%) patients [Table 2]. There was extension into the graft in two patients. Two were bilateral, and the rest had single-sided involvement. Four required surgical treatment, two requiring debridement and graft explant, while the others required pedicled muscle flap cover after debridement. The rest were managed in the ward with antibiotics and daily dressings. On univariate analysis, the presence of diabetes and end-to-end configuration of aortic anastomosis proved significant predictors for the development of groin infection.
Table 2: Organisms isolated from infected groins

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Six patients had graft infections, out of which one had a graft blow out and proved fatal. Three patients underwent debridement, partial graft explant, and pedicled muscle flap cover. One patient underwent debridement and graft excision followed by axillofemoral bypass. One patient was managed with long-term antibiotics and dressings. The microbiological profile was similar to groin infection, showing a predominance of Gram-negative bacteria, with only two cultures isolating Methycillin Sensitive Staphylococcus aureus. On univariate analysis, women showed predisposition towards developing graft infection.

Sixteen patients (11.4%) had early graft thrombosis, 13 of which were managed with emergency thrombectomy, and three were managed with therapeutic anticoagulation. On univariate analysis, acute presentation, nonatherosclerotic etiology, endarterectomy and end to side configuration of aortic anastomosis have been shown to predict early graft thrombosis.

Intermediate graft thrombosis was seen in twelve (8.6%) patients. Four patients who underwent revascularization for early graft thrombosis developed intermediate thrombosis. A historical correlation to patients who restarted smoking and stopped antiplatelets/statins was observed in patients with intermediate graft thrombosis. Eight patients were managed with therapeutic anticoagulation, one underwent graft thrombectomy, two had a bypass procedure and one had to undergo above knee amputation because of overwhelming sepsis. On univariate analysis, the presentation (acute vs. chronic) was a significant predictor for developing intermediate thrombosis.

Late graft thrombosis was seen in eight (5.8%) patients. Two underwent revascularization procedures (graft thrombectomy, axilloprofunda bypass), two had concomitant graft infection and required graft explant, three required major secondary amputations and one patient developed fatal spinal ischemia. On univariate analysis, women and claudicants were predisposed to have late graft thrombosis.

Eighteen patients had primary amputations. The presence of hypertension was shown to have a positive predictive value against primary amputation. Twenty-one patients required secondary amputations. Patients with CKD, femoral endarterectomy, and infra inguinal disease were prone to secondary amputations.

Kaplan Meier analysis curves were plotted [Figure 1], [Figure 2], [Figure 3], based on the reporting standards proposed by Rutherford et al. to look at primary, secondary patency rates, and amputation-free survival. At 5 years, the primary patency was 76.9%, and secondary patency was 94.2%. At 5 years, 76.9% of the population were amputation free.
Figure 1: Kaplan meier curve on primary patency

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Figure 2: Kaplan meier curve on secondary patency

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Figure 3: Kaplan meier curve on amputation free survival

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Historical Perspective: We have carried out a comparison analysis [Table 3] between our historical cohort, analyzing 99 patients undergoing ABB for AIOD over 6 years (January 2005 to December 2010) with our current cohort of analogous patients.
Table 3: Comparing historical and contemporary cohorts

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Comparison analysis showed a rise in all risk factors compared to the old cohort, though some did not achieve statistical significance. There was a significant increase in smoking, dyslipidemia, coronary artery disease, CKD, and flow-limiting infra-inguinal disease. Atherosclerosis remained the predominant etiology with a decrease in patients having other etiologies. There was a significant increase in the use of wider grafts, 14 mm × 7 mm as compared to 12 mm × 6 mm.

The 30-day mortality remained unchanged. There was a significant increase in intermediate graft thrombosis and major primary amputations. There was an increasing trend in perioperative MI and pulmonary complications though it did not reach statistical significance. The groin complications and the incidence of graft infection remained unperturbed.


  Discussion Top


India is encountering a phase of epidemiological shift with urbanization, adverse lifestyle choices, nutritional changes, which pave a way toward metabolic risk factor transition.[6] This study was devised to examine how these effects translate into outcomes in present-day individuals affected with AIOD undergoing aortic bifurcated graft procedures. We have compared the clinical profiles of the contemporary cohort to our previously published data,[7] chronicling our experience at one of the largest tertiary referral centers in India.

The demographic profile remained unchanged, with AIOD predominantly impacting young males, who remain a mean of 10 years younger than their western counterparts.[8] AIOD remains infrequent in women, with no rise in its incidence as seen by Kakkos et al. Mean time to presentation has slightly reduced, most patients present more than 1 year after symptom onset, making late presentation with advanced ischemia the norm. Close to 90% of the patients present with tissue loss, which remains the sentinel factor bringing about outcomes, diverse, from western literature.[8],[9],[10],[11] Atherosclerosis affects 85% of the patients who underwent aortic bifurcated procedures, with a significant decrease in open reconstruction for etiologies such as vasculitis and prothrombotic states over the past 10 years. There has been a significant increase in smoking, dyslipidemia, CAD, and CKD in our contemporary cohort. This aggravated risk factor profile is likely contributing to the significant rise in flow-limiting infra inguinal disease, which in turn, attributes to increase in major primary amputations in the contemporary cohort. Despite the challenging risk factor profile, there is little change in postoperative outcomes, which may be a byproduct of improved preoperative optimization and optimization of anesthetic techniques. We also noted a significant change in the favored graft size, with a preference of 14 mm × 7 mm grafts over 12 mm × 6 mm grafts, still significantly smaller compared to other reviews, signifying the small aortic size in Indian patients.[12]

The 30-day mortality remains the same, despite adverse clinical profile and is similar to that seen in various other reviews. Fatal MI is the leading cause attributing to mortality. It has been proven that there is a significant co-relation between AIOD and CAD.[13] The American Heart Association guidelines recommend (Grade IIa) preprocedure stress testing or a coronary angiogram in all high-risk vascular procedures.[14] The cardiac workup in our unit is limited to clinical evaluation, ECG, and ECHO. In view of the significant cardiac mortality along with increase in the incidence of CAD, in comparison with our historical cohort, the institution of routine preoperative stress testing/coronary angiogram in future may assist us in shrinking mortality outcomes.

Pulmonary complications remain the leading cause of medical morbidity in our patients. Our rates have been significantly higher than that quoted in literature.[8] This may be attributed to the predominant smokers in our cohort. Since the past 30 years, our operative technique has employed a vertical midline incision for aortic exposure requiring general anesthesia. Recent authors have shown that transverse abdominal incision along with regional anesthetic techniques such as spinal and epidural anesthesia provides good access as well as improved outcomes in the form of decreased hospital stay and pulmonary morbidity.[15],[16],[19] Adapting this observation, to our future clinical practice, may afford improvement in our morbidity profile.

Though groin complications and graft infection remain unchanged in comparison to our historical cohort, we note that they are higher in contrast to published literature.[9] This may be explained by a high incidence of tissue loss with secondary infection in Indian patients at presentation, especially, as cultures extracted from groin wounds/grafts, are gram-negative and polymicrobial. We employ vertical groin incision for femoral artery exposure in our patients. Advocates of transverse groin incision have noted a reduced incidence of groin wound complications and wound infection, which may contribute to reduced incidence of graft infection.[18],[19] Adapting this to our practice shows a promise to alter our wound complication rates.

Our primary patency rates are slightly lower than standards,[9],[10] which may be attributable to mean younger age which predisposes to aggressive atherosclerotic disease and higher incidence of patients with CLTI, who have been shown to have poor patencies than claudicants.[10] Compared to our historical cohort, there is a significant increase in intermediate thrombosis in our recent patients. We have noted that most patients with intermediate graft thrombosis have restarted their smoking. Our 5-year amputation-free survival rate is 76.9%, which is on par with that, quoted in literature.[20]

It has been predicted that optimal risk factor control prevents up to 1,00,000 cardiovascular deaths per year.[21] In addition, disease prevention in terms of focused education on risk factor profile to vulnerable populations may help in further advancing our cause.

The major limitations of our study include the inherent bias associated with the retrospective arm and the variable follow-up with irregular surveillance intervals. Intra-operative details such as the cross-clamping time, the intraoperative hemodynamics were unaccounted for.


  Conclusions Top


Our study highlighted the epidemiological shift transpiring in patients affected by AIOD in the Indian subcontinent. Despite hostile clinical profiles, our outcomes remain unchanged and are comparable to western literature. With the aggressive increase in CAD, preoperative coronary angiogram may have a role in affecting mortality outcomes in our patients. Adapting technical alterations like transverse incisions for aortic and femoral exposure and enhancement in employing regional anesthetic techniques could improve the prevalence of perioperative morbidity. The fascinating history of aortic surgery endures with a promise to get better.

Acknowlegment

We would like to thank Miss Malavika Babu, Department of Biostatistics, CMC Vellore, for statistical input.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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Rangel A, Albarrán H, Solorio S, Hernández-González MA. Angiographic concurrence of coronary artery disease and aortoiliac lesions. Angiology 2002;53:685-92.  Back to cited text no. 13
    
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Fleisher LA, Fleischmann KE, Auerbach AD, Barnason SA, Beckman JA, Bozkurt B, et al. 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery: Executive summary: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation 2014;130:2215-45.  Back to cited text no. 14
    
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