Biological solutions to aortic root replacement: valve-sparing versus bioprosthetic conduit‡

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Three Arterial Grafts Improve Late Survival:A Meta-Analysis of Propensity-Matched Studies

Background: Little evidence shows whether a third arterial graft provides superior outcomes compared with the use of 2 arterial grafts in patients undergoing coronary artery bypass grafting. A meta-analysis of all the propensity score-matched observational studies comparing the long-term outcomes of coronary artery bypass grafting with the use of 2-arterial versus 3-arterial grafts was performed. Methods: A literature search was conducted using MEDLINE, EMBASE, and Web of Science to identify relevant articles. Long-term mortality in the propensity score-matched populations was the primary end point. Secondary end points were in-hospital/30-day mortality for the propensity score-matched populations and long-term mortality for the unmatched populations. In the matched population, time-to-event outcome for long-term mortality was extracted as hazard ratios, along with their variance. Statistical pooling of survival (time-to-event) was performed according to a random effect model, computing risk estimates with 95% confidence intervals. Results: Eight propensity score-matched studies reporting on 10 287 matched patients (2-arterial graft: 5346; 3-arterial graft: 4941) were selected for final comparison. The mean follow-up time ranged from 37.2 to 196.8 months. The use of 3 arterial grafts was not statistically associated with early mortality (hazard ratio, 0.93; 95% confidence interval, 0.71-1.22; P=0.62). The use of 3 arterial grafts was associated with statistically significantly lower hazard for late death (hazard ratio, 0.8; 95% confidence interval, 0.75-0.87; P<0.001), irrespective of sex and diabetic mellitus status. This result was qualitatively similar in the unmatched population (hazard ratio, 0.57; 95% confidence interval, 0.33-0.98; P=0.04). Conclusions: The use of a third arterial conduit in patients with coronary artery bypass grafting is not associated with higher operative risk and is associated with superior long-term survival, irrespective of sex and diabetic mellitus status

Impact of preoperative pulmonary function on outcomes after open repair of descending and thoracoabdominal aortic aneurysms

Objective To evaluate the impact of preoperative pulmonary function on outcomes after open repair of descending thoracic (DTA) and thoracoabdominal aortic (TAAA) aneurysms. Methods The outcomes of patients undergoing open repair of DTA or TAAA were analyzed in relation to the results of preoperative pulmonary function tests. Receiver operating characteristic was adopted to assess the effect of forced expiratory volume in one second (FEV1) on the incidence of mortality. Logistic regression analysis and propensity score matching were used. Results Between 1997 and 2015, 726 patients underwent open DTA or TAAA repair. Pulmonary function tests were available in 711 (97.9%). Receiver operating characteristic analysis revealed the cutoff value of FEV1 to be 50%. Propensity score matching led to 149 pairs of patients with FEV1 below and above 50% with only limited residual imbalance. In the matched population operative mortality was 11.4% and 6.0% in patients with FEV1 ≤ 50% and FEV1 ≥ 51%, respectively (P = .10). The incidence of major adverse events was 33.1% in cases with FEV1 ≤ 50% and 19.5% in those with FEV1 ≥ 51% (P = .008). FEV1 ≤ 50% was associated with a 6.99× increase in the risk of major postoperative adverse events at logistic regression analysis. Conclusions Preoperative FEV1 < 50% is strongly predictive of increased respiratory failure, tracheostomy, and operative mortality in patients undergoing open DTA/TAAA repair. For these very high-risk patients with either extensive TAAAs or anatomy unsuitable for endovascular repair, medical therapy may offer the best long-term survival

Incomplete revascularization and long-term survival after coronary artery bypass surgery

Background We sought to investigate the impact of incomplete revascularization (IR) on long-term survival after isolated coronary artery bypass grafting (CABG). The possible interaction between IR and off-pump surgery was also explored. Methods A total of 13,701 patients with multivessel disease undergoing CABG were included in the analysis. All patients received left internal thoracic artery (LITA) to the left anterior descending artery (LAD) territory. IR was defined as at least one diseased arterial territory (right coronary artery [RCA] and/or circumflex [CX] artery) incompletely revascularized. Results Overall, 3107 (22.7%) patients received IR. After propensity score matching, IR did not increase all-cause death in the overall group (HR 1.09; 95%CI 0.96\u20131.22; P = 0.17). However, when both RCA and CX artery were incompletely revascularized, late survival was significantly lower (HR 2.15; 95%CI 1.57\u20132.93). IR was associated with a higher risk of death after off-pump (HR 1.26; 95%CI 1.05\u20131.49) regardless the extent of IR. After on-pump, IR significantly affected survival only when both RCA and CX artery only were incompletely revascularized (HR 2.32; 95%CI 1.27\u20134.22). Conclusions The present analysis shows that in patients with LITA-LAD graft the impact of IR on survival is marginal when only one coronary territory is left ungrafted. When both the RCA and CX territory remain unrevascularized the survival rate is significantly reduced. IR after off-pump CABG is associated with significantly lower survival and affects long-term outcome even when only one coronary territory is not revascularized

Techniques for intraoperative graft assessment in coronary artery bypass surgery

Early graft patency is a major determinant of morbidity and mortality following coronary artery bypass surgery. Long-term graft failure is caused by intimal hyperplasia and atherosclerosis, while early failure, especially in the first year, has been attributed, in part, to surgical error. The need for intraoperative graft evaluation is paramount to determine need for revision and ensure future functioning grafts. Transit time flowmetry (TTFM) is the most commonly used intraoperative modality, however, only about 20% of cardiac surgeons in North America use TTFM. When combined with high resolution epicardial ultrasonography, TTFM provides high diagnostic yield. Fluorescence imaging can provide excellent visualization of the coronary and graft vasculature; however, data on this subject is limited. We herein examine the literature and discuss the available techniques for graft assessment along with their limitations

Open repair of descending and thoracoabdominal aortic aneurysms in octogenarians

Objective: Despite improved outcomes for open repair of descending thoracic aneurysm (DTA) and thoracoabdominal aortic aneurysm (TAAA), these operations remain challenging in octogenarians. Patients unsuitable for thoracic endovascular aortic repair require open surgery to avoid catastrophic rupture. We analyzed our results for DTA/TAAA repair in these elderly patients. Methods: Our institutional aortic database was queried to identify those ≥80 years old and those <80 years old undergoing open DTA/TAAA repair. Logistic and Cox regression analyses were used to account for confounders and to identify predictors of perioperative and long-term outcomes. Results: From 1997 to 2017, there were 783 patients who underwent open repair of DTA or TAAA; 96 (12.3%) were ≥80 years old. Octogenarians were more likely to be female (P =.018), with chronic pulmonary disease (P =.012), severe peripheral vascular disease (P <.001), and hypertension (P =.025). Degenerative aneurysms were more common among octogenarians (P <.001), whereas chronic and acute dissections were more common among those younger than 80 years (P <.001 for both). Operative mortality was 5.6% and was not negatively affected by advanced age (<80 years, 5.7%; ≥80 years, 5.6%; P =.852). Other than an increased incidence of left recurrent nerve palsy in the younger cohort (<80 years, 6.7%; ≥ 80 years, 1.0%; P =.029), there were no significant differences in the incidence of major postoperative complications. Logistic regression modeling showed that age ≥80 years was not predictive of operative mortality or postoperative complications. A greater percentage of octogenarians had aortic reconstruction with a clamp and sew strategy (85.4% vs 61.6%; P <.001), which led to significantly shorter cross-clamp times in this cohort (26.6 minutes vs 30.7 minutes; P <.004). In octogenarians, the incidence of major postoperative adverse events was associated with extent II aneurysms (odds ratio, 2.6; P <.025). Short- and long-term survival was significantly reduced in octogenarians. Conclusions: In select octogenarians, open repair of DTA/TAAA can be performed with acceptable risk. A simplified surgical approach may provide the best opportunity for a successful outcome

Application of roller compacted concrete for road pavements in Sri Lanka

There is a great need to construct more durable roads such as concrete roads in Sri Lanka since the government is spending a considerable amount of money every year to maintain the national road network which has been constructed using with either conventional asphalt concrete or bituminous paving materials. This research was carried out mainly to explore the possibility of introducing more durable and cost effective Roller Compacted Concrete for road pavements in Sri Lanka. The structural behavior of Roller Compacted Concrete pavement (RCCP), which is a rigid pavement, is completely different from conventional asphalt pavements which are designed as flexible pavements. Since RCCP is not currently used in Sri Lanka there is no local standards available for design and construction of RCCP. An extensive literature review was carried out regarding the design of rigid pavements practiced in other countries. The rigid pavements can be designed using different types of design methods for given conditions. However, out of those methods, American Association of State Highway Traffic Organization method (AASHTO) and Portland Cement Association (PCA) method are popular in the countries where rigid pavements are used. Out of these two methods AASHTO method uses more parameters in designing the pavement thickness. Therefore, parametric study was carried out to investigate the effect of each parameter used in AASHTO method. And also a computer program was developed based on PCA method to carry out the thickness design procedure effectively, as it is more suitable for low volume traffic conditions. An experimental investigation was carried out to formulate a mix design procedure for RCC using local materials. Since the thickness of RCCP depends on the flexural strength of RCC, tests were carried out to investigate the factors affecting the flexural strength of RCC and also other properties such as wet density, compressive strength and drying shrinkage. New test methods were developed to measure these properties specially the flexural strength and wet density incorporating actual conditions of RCC such as actions of static and vibrating rollers. A new apparatus was developed to measure the wet density by modifying the conventional V-B apparatus where vibration as well as known static pressure can be applied to compact concrete. Furthermore, use of chemical and mineral admixtures to improve the properties of RCC was also investigated. Based on the results of experimental investigations a mix design procedure for RCC was proposed