Why Are We Weighting? Understanding the Estimates From Propensity Score Weighting and Matching Methods

BACKGROUND

Propensity score methods are used in observational studies to compensate for the lack of random allocation by balancing measured baseline characteristics between treated and untreated patients. We sought to explain the treatment effect estimates derived from different propensity score methods.

METHODS

We performed a retrospective analysis of long-term mortality after single internal mammary artery versus bilateral internal mammary artery (BIMA) conduit in 47 984 index isolated coronary artery bypass grafting procedures from 1992 to 2014 in the Northern New England Cardiovascular Disease Study Group registry using multivariable Cox regression, 1:1 propensity score matching, inverse probability weighting (IPW) among the treated, and IPW among the overall population treatment estimates.

RESULTS

The mean duration of follow-up was 13.2 (interquartile range, 7.4-17.7) years. In multivariable Cox regression, the adjusted hazard ratio for mortality was 0.83 (95% CI, 0.75-0.92) in patients receiving BIMA compared with a single internal mammary artery. The 1:1 propensity matched (hazard ratio, 0.79 [95% CI, 0.69-0.91]) and IPW among the treated (hazard ratio, 0.83 [95% CI, 0.75-0.92]) estimates showed a protective treatment effect of BIMA use on mortality. However, the IPW estimate of treatment effect for the overall population showed an increased risk of mortality after BIMA that was not statistically significant (hazard ratio, 1.08 [95% CI, 0.94-1.24]).

CONCLUSIONS

While the multivariable Cox regression, 1:1 propensity matching, and IPW treatment effect in the treated estimates demonstrate that BIMA was associated with a statistically significantly decreased risk of mortality, the IPW treatment effect in the average study population showed an increased risk of mortality associated with BIMA that was not statistically significant. This is attributed to the different populations (weighted to look like the overall study population versus treated group) represented by the 2 IPW approaches. Determining how the study population is balanced is a large driver of the treatment effect. Ultimately, the treatment effect estimate desired should drive the choice of the propensity score method.

Status of cardiovascular surgery in Japan between 2017 and 2018: A report based on the Cardiovascular Surgery Database. 2. Isolated coronary artery bypass surgery

BACKGROUND

Clinical outcomes (as national clinical data) of isolated coronary artery bypass grafting have been successively reported, based on data registered in the Japan Cardiovascular Surgery Database, since 2013. In this study, we analysed the clinical results of isolated coronary artery bypass from 2017 to 2018 as a biannual report.

METHODS

Data from the Japan Cardiovascular Surgery Database on isolated coronary artery bypass performed in 2017 and 2018 were reviewed for preoperative characteristics, postoperative outcomes, and choice of graft material for the left anterior descending artery.

RESULTS

Isolated off-pump coronary artery bypass was performed in 54.6% (n = 14,684) of all coronary artery bypass cases (n = 26,913), and graft material for the left anterior descending artery was the left internal thoracic artery in 76.4% of cases and the right internal thoracic artery in 19.0% of cases. Operative mortality was 1.5% in elective cases (on-pump coronary artery bypass 1.9% and off-pump 1.2%, p < 0.001), 7.4% in emergency cases (on-pump 10.2% and off-pump 4.3%, p < 0.001), and 2.5% overall. Postoperative morbidity was generally lower in off-pump coronary artery bypass. The severity of surgery with expected mortality, evaluated using JapanSCORE II, is increasing every year.

CONCLUSIONS

Our findings suggest that short-term operative results for isolated coronary artery bypass are stable, and operative candidates are shifting to higher-risk patients.

Branched internal mammary conduit permits non-sequenced total arterial revascularization

Recent trends in cardiac surgery have encouraged total arterial coronary revascularization, citing advantages in long-term patency and overall mortality. Often relying on sequenced, composite, and free-graft strategies, total arterial coronary revascularization is limited by conduit availability and surgical complexity. We present the use of bilateral internal mammary artery grafts to achieve nonsequential 3-vessel total arterial coronary revascularization using the preserved distal bifurcation of the right internal mammary artery. Utilization of distal internal mammary artery branches should be considered a viable strategy in select patients and can broaden the opportunities for total arterial coronary revascularization in patients with multivessel coronary disease.

Hybrid Coronary Revascularization Versus Conventional Coronary Artery Bypass Surgery: Utilization and Comparative Outcomes

BACKGROUND

Hybrid coronary revascularization (HCR) treats multivessel coronary artery disease by combining a minimally invasive surgical approach to the left anterior descending artery with percutaneous coronary intervention for non-left anterior descending diseased coronary arteries. The objective of this study is to compare HCR and conventional coronary artery bypass graft (CABG) surgery medium-term outcomes.

METHODS

Data from multivessel disease patients in New York's cardiac surgery and percutaneous coronary intervention registries in 2010 to 2016 were used to compare mortality and repeat revascularization rates for HCR and conventional CABG after using propensity matching to reduce selection bias.

RESULTS

There was a total of 303 HCR (0.80%) patients and 37 556 conventional CABG patients after exclusions. After propensity matching, the respective median follow-up times were 3.72 years and 3.76 years. There was no difference between HCR and conventional CABG in survival at 6 years (80.9% versus 85.8%%, adjusted hazard ratio, 1.44 [0.90-2.31]), but HCR had higher mortality excluding deaths during the first year (adjusted hazard ratio, 1.88 [1.10-3.23]). Conventional CABG patients were more likely to be free from repeat revascularization at 6 years than HCR patients (88.2% versus 76.6%; hazard ratio, 2.22 [1.44-3.42]).

CONCLUSIONS

HCR is rarely performed for patients with multivessel coronary artery disease. HCR and conventional CABG had no different 6-year mortality rates, but HCR had higher mortality after 1 year and higher rates of subsequent revascularization that were caused by both the need for repeat revascularization in the left anterior descending artery where minimally invasive CABG was performed, and in the coronary arteries where percutaneous coronary intervention was performed. Graphic Abstract: A graphic abstract is available for this article.

An unusual "venous circle" of the internal mammary vein encountered during microvascular anastomosis and implications for practice

The internal mammary vessels are commonly used for anastomosis in breast reconstruction. The anatomy when using the 2nd ICS has been shown to be predictable and hence preferentially used by the senior author. We present an unusual case of internal mammary vein bifurcation and immediate confluence forming a 'venous circle'.

VSMC-Specific Deletion of FAM3A Attenuated Ang II-Promoted Hypertension and Cardiovascular Hypertrophy

RATIONALE

Dysregulated purinergic signaling transduction plays important roles in the pathogenesis of cardiovascular diseases. However, the role and mechanism of vascular smooth muscle cell (VSMC)-released ATP in the regulation of blood pressure, and the pathogenesis of hypertension remain unknown. FAM3A (family with sequence similarity 3 member A) is a new mitochondrial protein that enhances ATP production and release. High expression of FAM3A in VSMC suggests it may play a role in regulating vascular constriction and blood pressure.

OBJECTIVE

To determine the role and mechanism of FAM3A-ATP signaling pathway in VSMCs in the regulation of blood pressure and the pathogenesis of hypertension.

METHODS AND RESULTS

In the media layer of hypertensive rat and mouse arteries, and the internal mammary artery of hypertensive patients, FAM3A expression was increased. VSMC-specific deletion of FAM3A reduced vessel contractility and blood pressure levels in mice. Moreover, deletion of FAM3A in VSMC attenuated Ang II (angiotensin II)-induced vascular constriction and remodeling, hypertension, and cardiac hypertrophy in mice. In cultured VSMCs, Ang II activated HSF1 (heat shock factor 1) to stimulate FAM3A expression, activating ATP-P2 receptor pathway to promote the change of VSMCs from contractile phenotype to proliferative phenotype. In the VSMC layer of spontaneously hypertensive rat arteries, Ang II-induced hypertensive mouse arteries and the internal mammary artery of hypertensive patients, HSF1 expression was increased. Treatment with HSF1 inhibitor reduced artery contractility and ameliorated hypertension of spontaneously hypertensive rats.

CONCLUSIONS

FAM3A is an important regulator of vascular constriction and blood pressure. Overactivation of HSF1-FAM3A-ATP signaling cascade in VSMCs plays important roles in Ang II-induced hypertension and cardiovascular diseases. Inhibitors of HSF1 could be potentially used to treat hypertension.

Natural internal thoracic-to-coronary artery collateral network

We describe a rare case of three-vessel coronary disease in a 67-year-old man who had spontaneous communication between the left internal mammary artery and the left anterior descending artery. We decided to perform elective coronary artery bypass grafting. However, he died from sudden cardiac arrest before surgery.

Characterisation of vasodilatory responses in the presence of the CGRP receptor antibody erenumab in human isolated arteries

BACKGROUND

Migraine is associated with activation of the trigeminovascular system, release of calcitonin gene-related peptide (CGRP) and dilation of dural arteries. Novel treatments target calcitonin gene-related peptide or its receptor, which are present in all vascular beds, raising cardiovascular concerns. Erenumab is a human CGRP-receptor antibody approved for the prophylactic treatment of migraine.

METHODS

We characterised the relaxant responses to CGRP in the absence and presence of erenumab (1 μM) in isolated human middle meningeal, internal mammary and (proximal and distal) coronary arteries. Furthermore, in human internal mammary arteries from cardiovascularly-compromised patients, we assessed the pharmacological specificity of erenumab by investigating whether the vasodilatory responses to acetylcholine, sodium nitroprusside, pituitary adenylate cyclase activating polypeptide-38 (PACAP), vasoactive intestinal peptide and nicardipine, along with the vasoconstrictor responses to dihydroergotamine, were modified by erenumab.

RESULTS

Calcitonin gene-related peptide induced concentration-dependent vasodilatory responses in all vessels studied that were significantly antagonised by erenumab. In human internal mammary arteries from cardiovascularly-compromised patients, the responses to acetylcholine, sodium nitroprusside, PACAP, vasoactive intestinal peptide, nicardipine and dihydroergotamine were unaffected by erenumab.

CONCLUSION

Erenumab inhibits calcitonin gene-related peptide-induced vasodilatory responses in human middle meningeal arteries, human internal mammary arteries and human coronary arteries. Moreover, erenumab shows functional specificity as no interaction was observed with the relaxant responses to several vasodilators, nor the dihydroergotamine-dependent vasoconstrictor responses.

Left lateral intercostal region versus subxiphoid position for pleural drain during elective coronary artery bypass graft surgery: randomized clinical trial

BACKGROUND

The pleural drain insertion site after coronary artery bypass graft (CABG) surgery may alter lung function, especially respiratory muscle strength. The main objective of this study was to compare the effectiveness and safety of use of the left lateral intercostal region versus the subxiphoid position for pleural drainage during elective CABG surgery using extracorporeal circulation (ECC).

DESIGN AND SETTING

Randomized trial conducted in a tertiary-level hospital in Porto Alegre, Brazil.

METHODS

48 patients were assigned to group 1 (pleural drain in the left lateral intercostal region) or group 2 (pleural drain in the subxiphoid position). Respiratory muscle strength was measured in terms of maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP), in cmH2O, by means of manovacuometry preoperatively, 24 and 72 hours after drain removal and before discharge from hospital. Painand dyspnea scales, presence of infections, pleural effusion and atelectasis, duration of drain use, drainage volumes and surgical reinterventions were also evaluated.

RESULTS

After adjustments, there were no significant differences between the groups at the end of the study (before discharge), in predicted percentages either for MIP (delta group 1: -17.21% versus delta group 2: -22.26%; P = 0.09) or for MEP (delta group 1: -9.38% versus delta group 2: -13.13%; P = 0.17). Therewere no differences between the groups in relation to other outcomes.

CONCLUSION

There was no difference in maximal respiratory pressures in relation to the pleural drain insertion site among patients who underwent CABG surgery using ECC.

TRIAL REGISTRATION

ReBEc V1111.1159.4447.

Dual inflow, total-arterial, anaortic, off-pump coronary artery bypass grafting: how to do it

Coronary surgery performed on an arrested heart, using one internal mammary artery and a saphenous vein carries two main potential drawbacks: the known failure rate of vein grafts and the relatively high rate of neurologic injury. To address these concerns, we describe a technique that achieves complete revascularization without manipulating the ascending aorta (anaortic, off-pump) and utilizing total arterial grafts. All patients undergo thorough preoperative investigation, including bilateral carotid, vertebral and subclavian artery Duplex ultrasounds. A pulmonary artery catheter, transoesophageal echocardiography, and point-of-care coagulation testing are used in each case. The left and right internal mammary arteries and non-dominant radial artery are harvested using a fully skeletonised technique. Wide bilateral extrapleural retrothymic tunnels are developed and the pericardium is opened widely to facilitate cardiac positioning. A tandem graft is constructed with the right internal mammary artery (RIMA) in situ and radial artery using an end-to-end anastomosis. This graft is brought into the pericardium and through the transverse sinus in order to graft the lateral and inferior walls with multiple sequential distal anastomoses. The left internal mammary artery (LIMA) in situ is used to graft the anterior wall. Four main cardiac positions (high and low lateral walls, inferior and anterior walls) are obtained using a combination of off-pump stabilizer positioning, alternate tension on pericardial 'heart-strings', table tilting and folded wet sponges. All distal anastomoses are performed using silastic intracoronary shunts and an off-pump myocardial stabilizer. All grafts are checked using transit-flow time measurements. Milrinone is continued overnight and dual antiplatelet therapy is continued for 3 months postoperatively.

Successful treatment of a ruptured left internal mammary artery aneurysm with a delayed diagnosis of type I neurofibromatosis

Neurofibromatosis type I (NF-1) induced vasculopathy is rare but catastrophic complication after aneurysmal rupture. We present the case of a 55-year-old female who developed hypovolemic shock because of left internal mammary artery (IMA) pseudoaneurysm rupture associated with NF-1. Even she was not detected NF-1 at the time of arrival in emergency room. We decided to perform percutaneous embolization instead of surgical approach. In this case, after intervention, the ruptured left IMA aneurysm was well treated. After 10 days, the patient discharged without any complications.

Hemoglobin A1c Levels Predicts Acute Kidney Injury after Coronary Artery Bypass Surgery in Non-Diabetic Patients

INTRODUCTION:

Elevated hemoglobin A1c levels in patients with diabetes mellitus have been known as a risk factor for acute kidney injury after coronary artery bypass grafting. However, the relationship between hemoglobin A1c levels in non-diabetics and acute kidney injury is under debate. We aimed to investigate the association of preoperative hemoglobin A1c levels with acute kidney injury in non-diabetic patients undergoing isolated coronary artery bypass grafting.

METHODS:

202 non-diabetic patients with normal renal function (serum creatinine <1.4 mg/dl) who underwent isolated coronary bypass were analyzed. Hemoglobin A1c level was measured at the baseline examination. Patients were separated into two groups according to preoperative Hemoglobin A1c level. Group 1 consisted of patients with preoperative HbA1c levels of < 5.6% and Group 2 consisted of patients with preoperative HbA1c levels of ≥ 5.6%. Acute kidney injury diagnosis was made by comparing baseline and postoperative serum creatinine to determine the presence of predefined significant change based on the Kidney Disease Improving Global Outcomes (KDIGO) definition.

RESULTS:

Acute kidney injury occurred in 19 (10.5%) patients after surgery. The incidence of acute kidney injury was 3.6% in Group 1 and 16.7% in Group 2. Elevated baseline hemoglobin A1c level was found to be associated with acute kidney injury (P=0.0001). None of the patients became hemodialysis dependent. The cut off value for acute kidney injury in our group of patients was 5.75%.

CONCLUSION:

Our findings suggest that, in non-diabetics, elevated preoperative hemoglobin A1c level may be associated with acute kidney injury in patients undergoing coronary artery bypass grafting. Prospective randomized studies in larger groups are needed to confirm these results.

Sectioned images and surface models of a cadaver for understanding the free vascularised anterior rib flap

BACKGROUND

The purpose of this study is to describe the vascularised anterior rib flap on sectioned images and surface models using Visible Korean for medical education and clinical training in the field of mandibular reconstructive surgery.

MATERIALS AND METHODS

Serially sectioned images of the thorax were obtained from a cadaver. Significant structures in the sectioned images were outlined and stacked to create a surface model.

RESULTS

The PDF file (8.45 MB) of the assembled models can be downloaded for free from our website (http://vkh.ajou.ac.kr/Products/PDF/Vascularized_anterior_rib_flap.zip). In this file, important anatomical structures related to the vascularised anterior rib flap can be examined in the sectioned images. All surface models and stereoscopic structures of the vascularised anterior rib flap are expressed in real time.

CONCLUSIONS

We hope that these state-of-the-art sectioned images, outlined images, and surface models will help students and trainees gain a better understanding of the anatomy of the vascularised anterior rib flap.

Frequency and Predictors of Internal Mammary Artery Graft Failure and Subsequent Clinical Outcomes: Insights From the Project of Ex-vivo Vein Graft Engineering via Transfection (PREVENT) IV Trial

BACKGROUND

The internal mammary artery (IMA) is the preferred conduit for bypassing the left anterior descending (LAD) artery in patients undergoing coronary artery bypass grafting. Systematic evaluation of the frequency and predictors of IMA failure and long-term outcomes is lacking.

METHODS AND RESULTS

The Project of Ex-vivo Vein Graft Engineering via Transfection (PREVENT) IV trial participants who underwent IMA-LAD revascularization and had 12- to 18-month angiographic follow-up (n=1539) were included. Logistic regression with fast false selection rate methods was used to identify characteristics associated with IMA failure (≥75% stenosis). The relationship between IMA failure and long-term outcomes, including death, myocardial infarction, and repeat revascularization, was assessed with Cox regression. IMA failure occurred in 132 participants (8.6%). Predictors of IMA graft failure were LAD stenosis <75% (odds ratio, 1.76; 95% confidence interval, 1.19-2.59), additional bypass graft to diagonal branch (odds ratio, 1.92; 95% confidence interval, 1.33-2.76), and not having diabetes mellitus (odds ratio, 1.82; 95% confidence interval, 1.20-2.78). LAD stenosis and additional diagonal graft remained predictive of IMA failure in an alternative model that included angiographic failure or death before angiography as the outcome. IMA failure was associated with a significantly higher incidence of subsequent acute (<14 days of angiography) clinical events, mostly as a result of a higher rate of repeat revascularization.

CONCLUSIONS

IMA failure was common and associated with higher rates of repeat revascularization, and patients with intermediate LAD stenosis or with an additional bypass graft to the diagonal branch had increased risk for IMA failure. These findings raise concerns about competitive flow and the benefit of coronary artery bypass grafting in intermediate LAD stenosis without functional evidence of ischemia.

CLINICAL TRIAL REGISTRATION

URL: http:/www.clinicaltrials.gov. Unique identifier: NCT00042081.

Retroaortic right internal thoracic artery grafting of circumflex artery targets

BACKGROUND

Retroaortic right internal thoracic artery grafting has failed to gain popularity. We aimed to delineate patient correlates of eligibility, distribution of targets, and effects of target remoteness on outcome and risk of retroaortic bleeding.

METHODS

Data of 861 patients undergoing skeletonized bilateral internal thoracic artery grafting (2007-2012) were analyzed according to retroaortic (n = 300) or T-graft configuration. Retroaortic graft subgroups were categorized according to proximal (first obtuse marginal, ramus) or distal (2nd, 3rd, or sequential 1st-2nd obtuse marginal) circumflex artery targets.

RESULTS

LOESS curve analyses revealed that taller patients had a higher likelihood of retroaortic grafting. The distribution of 337 retroaortic graft targets (300 patients) was first obtuse marginal in 74.5%, 2nd marginal in 12.4%, ramus in 11.2%, 3rd marginal in 1.9% and sequential 1st-2nd marginal in 12.3%. The success rate in reaching proximal and distal circumflex artery targets was 97% and 30%, respectively, 5-year survival (92.2%) and freedom from major adverse cardiac and cerebrovascular events (85.8%) were comparable between proximal and distal retroaortic graft subgroups. Distal circumflex artery targets had no effect on the occurrence of major adverse cardiac and cerebrovascular events. The incidence of retroaortic bleeding from skeletonized retroaortic grafts was 0.6%.

CONCLUSIONS

Taller patients have a greater likelihood of qualifying for retroaortic grafting. This technique is highly reproducible for proximal but not distal circumflex artery targets. Distal circumflex artery targets are not independent correlates of early or late adverse outcomes. The risk of retroaortic bleeding is low despite retroaortic right internal thoracic artery skeletonization.

Antegrade filling of mammary graft by inappropriately revascularized artery

A 57-year-old man underwent multiple-arterial revascularization including a sequential left internal mammary artery graft to the diagonal branch and left anterior descending coronary artery. Twenty-one months later, repeat angiography due to a new onset of chest discomfort confirmed string sign and nonfunctional proximal left internal mammary artery, and antegrade filling of the distal leg of the sequential graft and the left anterior descending artery through the diagonal branch. This is a known but uncommon angiographic finding that confirms the importance of eventual competitive flow.

Coronary artery surgery in a patient with grossly emphysematous lung

The pedicled left internal thoracic artery graft is the mandatory conduit in coronary artery bypass surgery. A grossly emphysematous lung may sometimes present a significant problem for positioning of the pedicled left internal thoracic artery conduit. An inverted pedicled left internal thoracic artery graft (internal thoracic artery transected near its origin, thus supplied by retrograde flow from superior epigastric and musculophrenic arteries) might occasionally be the conduit of choice for those patients.

Bilateral internal thoracic artery grafting in insulin-treated diabetes

BACKGROUND

We sought to assess the risk and late outcome of bilateral internal thoracic artery grafting in eligible insulin-treated diabetic subsets.

METHODS

147 insulin-treated diabetic patients undergoing arterial revascularization were grouped as: skeletonized bilateral internal thoracic artery (n = 83) or internal thoracic artery-radial artery (n = 64). Chronic lung disease or overweight and female constituted exclusion criteria for bilateral internal thoracic artery grafts.

RESULTS

Patients who had bilateral internal thoracic artery grafts were younger and comprised fewer females. Left-sided bilateral internal thoracic artery configurations were predominantly applied. Despite mean hemoglobin A1c of 8.0% ± 1% (range, 7%-13.5%) respective rates of deep sternal infection in bilateral internal thoracic artery and radial artery patients were 1.2% and 0%; superficial wound infection occurred in 3.1% and 3.6%, respectively. One sternoplasty was performed. Bilateral internal thoracic artery grafting did not correlate with sternal complications (odds ratio = 2.24, 95%CI: 0.56-8.95, p = 0.256). Of the radial artery conduits, 98% were adequate, and procurement-site complications occurred in 3.1%. Follow-up was 2-58 months (median, 25 months). Five-year survival was comparable in the 2 groups (p = 0.360). Bilateral internal thoracic artery grafting did not reduce late major adverse cardiac events (p = 0.729) or late mortality (p = 0.384).

CONCLUSIONS

Skeletonized bilateral internal thoracic artery grafts can be used with acceptable risk in a substantial portion of insulin-treated diabetic patients, so it should not be automatically denied, but the choice of such grafts is not associated with midterm cardiac benefits.

Internal thoracic artery: anatomical and biological characteristics revisited

The left internal thoracic artery has become the conduit of choice for coronary artery bypass grafting, due to its superior patency rates at 10 or more years with little or no evidence of atherosclerotic changes. Recent evidence indicates that a second internal thoracic artery graft provides improved results relative to overall survival and major cardiac and cerebrovascular event-free survival, and reduces the need for repeat revascularization. However, the routine use of bilateral internal thoracic arteries is limited due to a perceived higher incidence of deep sternal wound infection. The surgical anatomy, collateral blood supply to the sternum, and biological characteristics of internal thoracic artery conduits are reviewed.

Detection of Helicobacter pylori DNA in aortic and left internal mammary artery biopsies

We investigated the relationship between acute coronary ischemia and the presence of Helicobacter pylori DNA in aortic regions that were absent macroscopic atheromatous plaques. The study group (Group 1) consisted of 42 patients who underwent coronary artery bypass grafting. Biopsy samples were obtained from 2 different locations: from regions of the aorta that were free (macroscopically) of atheromatous plaque (Group 1A), and from the internal mammary artery (Group 1B). The control group (Group 2) of 10 patients who had no atherosclerotic vascular disease provided aortic tissue samples for comparison. The real-time polymerase chain reaction method was used to detect H. pylori DNA in all biopsy samples. Eleven of 42 aortic tissue samples (26%) in Group 1A were positive for H. pylori DNA. Neither biopsies from the left internal mammary arteries of those patients nor biopsies from the aortas of the control group (Group 2) were positive for H. pylori DNA. There was a statistically significant difference between 1A and 1B in terms of H. pylori positivity (P=0.001). In Group 1 as a whole, acute coronary ischemia was more prevalent in the H. pylori-positive patients than in the H. pylori-negative patients (P=0.001). To our knowledge, this is the 1st study to investigate the detection of H. pylori DNA in aortic biopsy samples that are macroscopically free of atheromatous plaque. Such detection in patients who have atherosclerotic coronary artery disease could be an important indication of the role of microorganisms in the pathogenesis of atherosclerosis.

Profulla Kumar Sen: his contributions to cardiovascular surgery

One of the most eminent cardiothoracic surgeons of India, Profulla Kumar Sen (1915-1982) had a keen interest in research and in the subsequent clinical application of knowledge gained in the laboratory. His most significant contributions are his pioneering work on a transmyocardial acupuncture technique for treatment of ischemic myocardium, on heart transplantation in canine models and later in human beings, and on a new technique for aortic arch replacement. Transmyocardial laser revascularization of the 1990s was but an extension of his mechanical myocardial acupuncture for the treatment of ischemic heart disease, which he introduced 30 years earlier. On 16 February 1968, after many years of preparation through work with animal models, P.K. Sen and his team performed the 1st cardiac transplantation in India and the 6th in the world.