Kim Christian Houlind

On-Pump Versus Off-Pump Coronary Artery Bypass Surgery in Elderly Patients Results From the Danish On-Pump Versus Off-Pump Randomization Study

Background— Conventional coronary artery bypass grafting performed with the use of cardiopulmonary bypass is a well-validated treatment for patients with ischemic heart disease. Off-pump coronary artery bypass grafting (OPCAB) has been suggested to reduce the number of perioperative complications, especially in elderly patients. Methods and Results— In a multicenter, randomized trial, we assigned 900 patients >70 years of age to conventional coronary artery bypass grafting or OPCAB surgery. After 30 days, a blinded end-point committee assessed whether a combined end point of death, stroke, or myocardial infarction had occurred. At baseline and 6 months postoperatively, self-assessed quality of life was measured with the Medical Outcomes Study Short Form-36 and EuroQol-5D questionnaires. A 6-month follow-up of mortality was performed through the Danish National Registry. The proportion of patients experiencing the combined end point within 30 days was 10.2% for conventional coronary artery bypass grafting and 10.7% for OPCAB. Implied risk difference of 0.4% (with a 95% confidence interval, −3.6 to 4.4) showed nonsignificance in a standard test for equality (P=0.83) and for noninferiority with an inferiority margin of 0.5% (P=0.49). At the 6-month follow-up, mortality was 4.7% compared with 4.2% (P=0.75). Both groups showed significant improvement in self-assessed health-related quality of life. Conclusions— Both conventional coronary artery bypass grafting and OPCAB are safe procedures that improved the quality of life when performed in elderly patients. No major differences in intermediate-term outcomes were found. However, the noninferiority of OPCAB with the prespecified margin could not be confirmed. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00123981.Background— Conventional coronary artery bypass grafting performed with the use of cardiopulmonary bypass is a well-validated treatment for patients with ischemic heart disease. Off-pump coronary artery bypass grafting (OPCAB) has been suggested to reduce the number of perioperative complications, especially in elderly patients. Methods and Results— In a multicenter, randomized trial, we assigned 900 patients >70 years of age to conventional coronary artery bypass grafting or OPCAB surgery. After 30 days, a blinded end-point committee assessed whether a combined end point of death, stroke, or myocardial infarction had occurred. At baseline and 6 months postoperatively, self-assessed quality of life was measured with the Medical Outcomes Study Short Form-36 and EuroQol-5D questionnaires. A 6-month follow-up of mortality was performed through the Danish National Registry. The proportion of patients experiencing the combined end point within 30 days was 10.2% for conventional coronary artery bypass grafting and 10.7% for OPCAB. Implied risk difference of 0.4% (with a 95% confidence interval, −3.6 to 4.4) showed nonsignificance in a standard test for equality ( P =0.83) and for noninferiority with an inferiority margin of 0.5% ( P =0.49). At the 6-month follow-up, mortality was 4.7% compared with 4.2% ( P =0.75). Both groups showed significant improvement in self-assessed health-related quality of life. Conclusions— Both conventional coronary artery bypass grafting and OPCAB are safe procedures that improved the quality of life when performed in elderly patients. No major differences in intermediate-term outcomes were found. However, the noninferiority of OPCAB with the prespecified margin could not be confirmed. Clinical Trial Registration— URL: . Unique identifier: [NCT00123981][1]. # Clinical Perspective {#article-title-28} [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT00123981&atom=%2Fcirculationaha%2F125%2F20%2F2431.atom

A New Control Volume Method for Calculating Valvular Regurgitation

BACKGROUND The purpose of the present study was to develop a new method of measuring heart valvular regurgitation based on control volume theory and to verify its accuracy in vitro and in vivo. Current methods of quantifying valvular regurgitation rely too much on assumptions about the flow field and therefore are difficult to apply in vivo. In particular, the proximal isovelocity surface area (PISA) method oversimplifies the proximal velocity field by assuming hemispherical isovelocity contours proximal to the orifice. This severely limits the applicability of the PISA method. Use of the basic control volume theory, however, removes the need to assume the manner in which the proximal flow accelerates toward the regurgitant orifice, the shape and size of the orifice, the shape of the orifice plate, and the non-newtonian behavior of the fluid. Apart from a correction that is necessary if the orifice plate is moving, the control volume method assumes only the incompressibility of the fluid and therefore is a potentially more accurate approach. In addition, the use of magnetic resonance imaging (MRI) precludes the need for an acoustic window. METHODS AND RESULTS MRI has been used to measure the three-dimensional velocity field proximal to regurgitant orifices, including single and multiple orifices and a cone-shaped orifice plate. Both steady (0 to 7.5 L/min) and pulsatile (2 and 3 L/min) flows were used. By intergrating this velocity over a control volume surrounding the orifice, we calculated the flow rate through the orifice. As a validation, the cardiac output of a 50-kg pig also was measured and was compared with thermodilution measurements. It was found that MRI could be used to measure the three-dimensional flow proximal to regurgitant orifices. This enabled the calculation of the flow rate through the orifice by integrating the velocity over the surface of a control volume covering the orifice. This flow rate correlated well with the actual rate (0.992; correlation line slope, 1.01). Care had to be taken, however, to exclude from the integration regions of aliased velocity. The cardiac output of the pig measured using MRI was in close agreement with the themodilution measurements. CONCLUSIONS Our new method of measuring valvular regurgitation has been shown to be very accurate in vitro and in vivo and therefore is a potentially accurate way to quantify valvular regurgitation.

Graft patency after off-pump coronary artery bypass surgery is inferior even with identical heparinization protocols: Results from the Danish On-pump Versus Off-pump Randomization Study (DOORS)

OBJECTIVE To determine whether graft patency after on-pump and off-pump coronary artery bypass surgery is similar when performed using the same heparinization protocol. METHODS In a randomized, controlled, multicenter trial, 900 patients more than 70 years of age received either on-pump or off-pump coronary artery bypass surgery. Heparin was given to achieve an activated clotting time of 400 seconds before arteriotomy in both groups. After the procedure, protamine sulfate was given to revert the activated clotting time to less than 120 seconds. Coronary angiography was performed 6 months after the operation and graft patency was assessed by independent blinded observers. RESULTS A total of 481 patients underwent angiography. In the off-pump group, 561 (79%) of 710 grafts were open, 65 (9%) were stenotic, and 84 (12%) were occluded. In the on-pump group, 549 (86%) of 650 grafts were open, 38 (5%) were stenotic, and 63 (9%) were occluded. The difference between the proportion of open grafts was statistically significant in favor of on-pump surgery (P=.01). The proportion of open left internal thoracic artery grafts was 95% in both groups. Perioperative use of intracoronary shunts did not increase the risk of stenosis of the coronary artery distal to the anastomosis. CONCLUSIONS Despite comparable heparinization, graft patency after off-pump surgery was inferior to that after on-pump surgery.

Serial magnetic resonance imaging of global and regional left ventricular remodeling during 1 year after acute myocardial infarction.

Biplane long-axis cine MRI was performed in 51 patients 1, 13, 26, and 52 weeks after their first AMI. LV mass index (LVMI) was significantly increased 1 week after AMI (84.3 ± 16.9 vs. 68.1 ± 11.4 g/m2 controls, n = 48, p < 0.001), presumably owing to edema of the infarcted myocardium. Six months after AMI, LVMI decreased to 76.5 ± 16.4 g/m2, but had again augmented after 1 year (81.8 ± 17.3 g/m2, p < 0.05), suggesting late, compensatory left ventricular hypertrophy. In patients treated with primary percutaneous transluminal coronary angioplasty, LVMI decreased 5% over 1 year, while LVMI increased 10% in patients receiving thrombolysis (p < 0.05). In the entire population, the global increase in LVMI 1 year after AMI seemed to reflect global cavity dilatation with unchanged thickness of the vital myocardium. In conclusion, in patients receiving contemporary treatment, LV remodeling only partially complied with the classical patho-anatomical concept.

Abdominal Aortic Diameter Is Increased in Males with a Family History of Abdominal Aortic Aneurysms: Results from the Danish VIVA-trial

OBJECTIVE To investigate, at a population level, whether a family history of abdominal aortic aneurysm (AAA) is independently related to increased aortic diameter and prevalence of AAA in men, and to elucidate whether the mean aortic diameter and the prevalence of AAA are different between participants with male and female relatives with AAA. DESIGN Observational population-based cross-sectional study. MATERIALS 18,614 male participants screened for AAA in the VIVA-trial 2008-2011 with information on both family history of AAA and maximal aortic diameter. METHODS Standardized ultrasound scan measurement of maximum antero-posterior aortic diameter. Family history obtained by questionnaire. Multivariate regression analysis was used to test for confounders: age, sex, smoking, comorbidity and medication. RESULTS From the screened cohort, 569 participants had at least one first degree relative diagnosed with AAA, and 38 had AAA. Participants with a family history of AAA (+FH) had a significantly larger mean maximum aortic diameter (20.50 mm) compared with participants without family history of AAA (-FH) (19.07 mm, p < .0001), and +FH with female relatives with AAA had significantly larger mean maximum aortic diameter (21.8 mm) than +FH with male relatives (19.9 mm, p = .007). Furthermore the prevalence of AAA was significantly higher among +FH (6.7%) compared with -FH (3.0%) with an odds ratio (OR) of 2.2 (95% CI: 1.6 to 3.2, p < .001) and +FH with female relatives with AAA had a more than two and a half times increased prevalence of AAA compared with +FH with male relatives with AAA with an OR of 2.65. CONCLUSIONS First-degree male relatives of AAA patients have wider aortas and a twofold higher prevalence of AAA compared with the age adjusted background population. The prevalence of AAA was markedly higher in participants related to female, rather than male, patients with AAA.

OPCAB surgery is cost-effective for elderly patients

Abstract Objective. To determine the cost-effective operative strategy for coronary artery bypass surgery in patients above 70 years. Design. Randomized, controlled trial of 900 patients above 70 years of age subjected to coronary artery bypass surgery. Patients were randomized to either on-pump or off-pump coronary artery bypass surgery. Data on direct and indirect costs were prospectively collected. Preoperatively and six months postoperatively, quality of life was assessed using EuroQol-5D questionnaires. Perioperative in-hospital costs and costs of re-intervention were included. Results. The Summary Score of EuroQol-5D increased in both groups between preoperatively and postoperatively. In the on-pump group, it increased from 0.75 (0.16) (mean (SD)) to 0.84 (0.17), while the increase in the off-pump group was from 0.75 (0.15) to 0.84 (0.18). The difference between the groups was 0.0016 QALY and not significantly different. The mean costs were 148.940 D.Kr (CI, 130.623 D.Kr–167.252 D.Kr) for an on-pump patient and 138.693 D.Kr (CI, 123.167 D.Kr–154.220 D.Kr) for an off-pump patient. The ICER base-case point estimate was 6,829,999 D.Kr/QALY. The cost-effectiveness acceptability curve showed 89% probability of off-pump being cost-effective at a threshold value of 269,400 D.Kr/QALY. Conclusions. Off-pump surgery tends to be more cost-effective than on-pump surgery. Long-term comparisons are warranted.

On-pump versus off-pump coronary artery bypass surgery: what is the status after ROOBY, DOORS, CORONARY and GOPCABE?

Off-pump coronary artery bypass surgery has been purported to be safer than conventional coronary artery bypass surgery performed using cardiopulmonary bypass. This theory was supported by a number of early series, but failed to be confirmed by a number of small, randomized, controlled trials. Conversely, it has been suggested that revascularization after off-pump surgery is associated with fewer grafts and lower graft patency, potentially leading to a higher risk of cardiovascular morbidity and need for repeated coronary interventions. Since 2009, four major randomized controlled trials have been published, increasing the level of evidence significantly.

The role of the angiosome model in treatment of critical limb ischemia

When performing revascularization of the lower limb, common clinical practice and recent guidelines include grafting of the” best vessel” which crosses the level of the ankle in order to restore pulsatile flow to the foot [1]. This may lead to either direct perfusion of the ische‐ mic area or – very often – indirect perfusion relying on collaterals surrounding the diseased zone. This strategy is different from the one used e.g. in coronary artery bypass surgery, where the aim is ”complete revascularization” i.e. performing bypasses to every diseased vascular territory [2].

Early results from an angiosome-directed open surgical technique for venous arterialization in patients with critical lower limb ischemia

Background Patients with critical lower limb ischemia without patent pedal arteries cannot be treated by the conventional arterial reconstruction. Venous arterialization has been suggested to improve limb salvage in this subgroup of patients but has not gained wide acceptance. We report our early experience after implementing deep and superficial venous arterialization of the lower limb. Materials and methods Ten patients with critical ischemia and without crural or pedal arteries available for conventional bypass surgery or angioplasty were treated with distal venous arterialization. Inflow was from the most distal unobstructed segment. Run-off was the dorsal pedal venous arch (n=5), the dorsal pedal venous arch and a concomitant vein of the posterior tibial artery (n=3), or the dorsal pedal venous arch and a concomitant vein of the common plantar artery (n=2) depending on the location of the ischemic lesion. Venous valves were destroyed using antegrade valvulotomes, guide wires, knob needles, or retrograde valvulotomes via an extra incision. Results Seven of the operated limbs were amputated after 23 (1–256) days (median [range]). The main reasons for amputation were lack of healing of either the original wound, of incisional wounds on the foot, or persisting pain at rest. In three cases, the bypass was open at the time of amputation. Two patients experienced complete wound healing after 231 and 342 days, respectively. By the end of follow-up, the last patient was ambulating with slow wound healing but without pain 309 days after surgery. Conclusion Venous arterialization may be used as a treatment of otherwise unsalveable limbs. The success rate is, however, limited. Technical optimization of the technique is warranted.

Five‐year outcomes following a randomized trial of femorofemoral and femoropopliteal bypass grafting with heparin‐bonded or standard polytetrafluoroethylene grafts

Cohort studies suggest superior long‐term patency of luminal heparin‐bonded polytetrafluoroethylene (Hb‐PTFE) bypass grafts compared with standard PTFE grafts. The aim of this study was to compare the outcomes of Hb‐PTFE grafts with those of standard PTFE grafts 5 years after a randomized trial.