What future for coronary artery bypass surgery.

The future of coronary artery bypass graft can be bright if cardiac surgeons will change the paradigm followed so far and will return in history, abandoning the current comfortable life and accepting the burden represented by the cost of innovation, which has a path already mapped out but not sufficiently trodden for guilty lack of commitment.

How to recycle a misused left internal thoracic artery: Tips and tricks.

In this case report, we describe how to recycle the left internal thoracic artery (LITA) when misused but not damaged. Eight years after a left anterior small thoracotomy followed by left anterior descending (LAD) stenting for STEMI in first postoperative day, a 67-years-old woman had an NSTEMI with angiographic evidence of intrastent re-stenosis with a perfectly patent LITA, harvested only from the fourth to the sixth intercostal space. During redo surgery, LITA was harvested as a pedicle from the anastomosis to the fourth intercostal space and primarily from the first to the fourth intercostal space. Special attention was paid at the level of the fourth intercostal space where the vessel was stuck to the sternum: a 15-blade was used being scissors or cautery too dangerous. At the end of harvesting, the LITA was full-length available for a new coronary anastomosis on LAD, distal to the previous one.

Aortic interleaflet triangles reshaping: hydrodynamic, kinematic and morphological effects in in-vitro analysis.

BACKGROUND AND AIM OF THE STUDY: Subcommissural triangles reshaping is a reparative technique used to remodel the ventriculo-aortic junction. The study aim was to evaluate, by means of in-vitro testing, the effects of this technique on hemodynamics, leaflet kinematics and aortic root functional unit morphology. METHODS: Twenty-one porcine aortic roots were tested in a pulsatile mock loop under basal conditions and after subcommissural triangles reshaping performed at 50% of the interleaflet triangles height. During each test, hydrodynamic quantities, high-speed digital videos and echocardiographic images were recorded. RESULTS: The comparison between pre- and post-surgery data showed a statistically significant increase in coaptation height (p < 0.01) and length (p < 0.01). Significant reductions were found in the virtual basal ring diameter (p < 0.01), sinus of Valsalva diameters (p < 0.01), maximum leaflet opening (p < 0.01), leaflet opening before rapid valve closing time (p < 0.01) and maximum opening area (p < 0.01). An opened valve time reduction (p <0.01) was observed due to an opening time reduction (p < 0.01), offset by a closed valve time increase (p < 0.01). A slow closing period increase (p < 0.07) and a rapid closing phase reduction (p < 0.01), were also highlighted without influence on the total closing time. A statistical, but not clinically significant, increase in pressure drop across the valve (p < 0.01) and an effective orifice area reduction (p < 0.01) were observed. CONCLUSION: Subcommissural triangles reshaping performed at 50% of the interleaflet triangles' height determines an increase in leaflet coaptation by remodeling the ventriculo-aortic junction. Some hydrodynamic and kinematic changes also occur, without any acute clinically threatening alterations.

Features of degenerative mitral valve prolapse in the North East of China: repair characteristics, and short-term follow-up results.

BACKGROUND: We aimed to assess the clinical and echocardiographic characteristics of patients who underwent surgery for degenerative mitral valve prolapse (MVP) in our center, and its relation to outcomes. METHODS: We enrolled 117 consecutive patients from North-East China with an echocardiographic diagnosis of MVP related mitral regurgitation (MR) between April 2018 and November 2019. A complexity scoring system was used for valve anatomy, and patients were re-evaluated at 3-6 months after surgery. RESULTS: Most patients (57.3%) were 40-59 years old. Ejection fraction was <60% in one third, and pulmonary hypertension was present in 64.3% of operated patients. Etiology was myxomatous in 58.9%, with flail as main lesion. Leaflet involvement was posterior in 59.8% patients, anterior in 32.5%, bileaflet in 6%, and commissural in 25.6%. Lesion score was intermediate in >50% of patients, and myxomatous lesions scored higher compared to fibroelastic deficiency (FED). Degree of MR left atrial volume and estimated wedge pressure were significantly higher in intermediate and complex lesions. Repair was performed in 93/101 patients (95.8% success rate). No in-hospital major adverse events, nor deaths at follow-up were reported. Residual MR was ≤ mild in 86.7% of patients at follow-up and was associated with FED etiology and complex lesions. CONCLUSIONS: Compared to Western countries, in our sample of Chinese population degenerative severe MR occurred in younger patients. The MVP lesion characteristics are similar, can be accurately detected by non-invasive preoperative evaluation, allowing predictable results. Advanced tailored repair techniques allow excellent immediate and short-term results regardless of the underlying complexity.

Committee Recommendations for Resuming Cardiac Surgery Activity in the SARS-CoV-2 Era: Guidance From an International Cardiac Surgery Consortium.

Recommendations for the safe and optimized resumption of cardiac surgery care, research, and education during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) era were developed by a cardiovascular research consortium, based in 19 countries and representing a wide spectrum of experience with COVID-19. This guidance document provides a framework for restarting cardiac surgery in the outpatient and inpatient settings, in accordance with the current understanding of SARS-CoV-2, the risks posed by interrupted cardiovascular care, and the available recommendations from major societies.

Aortic root performance after valve sparing procedure: a comparative finite element analysis.

David and Yacoub sparing techniques are the most common procedures adopted for the surgical correction of aortic root aneurysms. These surgical procedures entail the replacement of the sinuses of Valsalva with a synthetic graft, inside which the cusps are re-suspended. Root replacement by a synthetic graft may result in altered valve behaviour both in terms of coaptation and stress distribution, thus leading to the failure of the correction. A finite element approach was used to investigate this phenomenon; four 3D models of the aortic root were developed to simulate the root in physiological, pathological and post-operative conditions after the two different surgical procedures. The physiological 3D geometrical model was developed on the basis of anatomical data obtained from echocardiographic images; it was then modified to obtain the pathological and post-operative models. The effectiveness of both techniques was assessed by comparison with the first two simulated conditions, in terms of stresses acting on the root, leaflet coaptation and interaction between leaflets and the graft during valve opening. Results show that both sparing techniques are able to restore aortic valve coaptation and to reduce stresses induced by the initial root dilation. Nonetheless, both techniques lead to altered leaflet kinematics, with more evident alterations after David repair.

Minimally Invasive coronary surgery compared to STernotomy coronary artery bypass grafting: The MIST trial.

RATIONALE: Minimally invasive cardiac surgery has emerged as a safe alternative to standard cardiac surgery. Minimally invasive coronary surgery (MICS CABG) was developed to allow adequate exposure and complete revascularization in CABG from a small thoracotomy incision without cardiopulmonary bypass. Multiple studies have reported significant shorter length of hospital stay and earlier postoperative physical recovery for MICS CABG patients when compared to sternotomy CABG patients. However, there have been no convincing clinical trials that demonstrate improvement in post-operative quality of life for patients who undergo MICS CABG. STUDY DESIGN: The Minimally Invasive Coronary Surgery compared to Sternotomy Coronary Artery Bypass Grafting (MIST) trial is a multi-centered, prospective randomized controlled trial that compares the quality of life and recovery in the early post-operative period between patients undergoing MICS CABG versus patients undergoing sternotomy CABG. Patients will be randomized either to the MICS CABG group or the sternotomy CABG group, and the target enrollment is 88 patients per group. The primary outcome is quality of life assessment performed by SF-36 questionnaire at 1 month. CONCLUSION: The MIST trial is the first prospective study that compares the quality of life between MICS CABG and sternotomy CABG patients. The results of this trial may enhance the procedural desirability of MICS CABG by patients and provide an incentive for surgeons and institutions to increase the availability of MICS CABG in suitable patients.

Doppler derived quantitative flow estimate in coronary artery bypass graft: a computational multiscale model for the evaluation of the current clinical procedure.

In order to investigate the reliability of the so called mean velocity/vessel area formula adopted in clinical practice for the estimation of the flow rate using an intravascular Doppler guide wire instrumentation, a multiscale computational model was used to give detailed predictions on flow profiles within Y-shaped coronary artery bypass graft (CABG) models. At this purpose three CABG models were built from clinical patient's data and used to evaluate and compare, in each model, the computed flow rate and the flow rate estimated according to the assumption of parabolic velocity profile. A consistent difference between the exact and the estimated value of the flow rate was found in every branch of all the graft models. In this study we showed that this discrepancy in the flow rate estimation is coherent to the theory of Womersley regarding spatial velocity profiles in unsteady flow conditions. In particular this work put in evidence that the error in flow rate estimation can be reduced by using the estimation formula recently proposed by Ponzini et al. [Ponzini R, Vergara C, Redaelli A, Veneziani A. Reliable CFD-based estimation of flow rate in haemodynamics measures. Ultrasound Med Biol 2006;32(10):1545-55], accounting for the unsteady nature of blood, applicable in the clinical practice without resorting to further measurements.

Flow dynamics and wall shear stress in the left internal thoracic artery: composite arterial graft versus single graft.

OBJECTIVE: Phasic blood flow dynamics and wall shear stress (WSS) have the potential to directly modulate endothelial responses, playing an important role in the development of bypass graft occlusion. This study compares phasic blood flow velocity patterns and WSS of the left internal thoracic artery (LITA) used as a composite Y-graft (27 patients, Y-group) and as a single graft (24 patients, S-group) on the left anterior descending (LAD) coronary artery. METHODS: An intravascular Doppler-tipped guide wire was used for postoperative analysis of phasic blood flow velocity. Flow velocities were recorded proximally and distally into the LITA in both groups. Digitalized spectral velocities were acquired to compute systolic peak velocity, diastolic peak velocity, and average peak velocity. The ratio of diastolic to systolic peak velocity was computed (DSVR). WSS was calculated from graft flow velocity and vessel diameter. RESULTS: Proximal LITA in Y-group had greater average peak velocity (APV) (p=0.000), DSVR (p=0.026), flow volume (p=0.000), WSS (p=0.02), and diameter (0.019) than S-group. There were not significant differences for the distal LITA between the two groups. CONCLUSIONS: The LITA shows a marked adaptability to flow dynamics. The proximal tract of the LITA in Y-group is able to match increased flow requirements, probably through the release of endothelial vasoactive mediators. Flow velocity spectra acquired in the proximal LITA in Y-group resemble the biphasic coronary artery pattern with a clear diastolic predominance. This pattern is probably consequence of the increase of blood flow due to the lower vascular resistance of the Y-graft system and to the active dilatation of the LITA.

A geometric approach to aortic root surgical anatomy.

OBJECTIVES: The aim of this study was the analysis of the geometrical relationships between the different structures constituting the aortic root, with particular attention to interleaflet triangles, haemodynamic ventriculo-arterial junction and functional aortic annulus in normal subjects. METHODS: Sixteen formol-fixed human hearts with normal aortic roots were studied. The aortic root was isolated, sectioned at the midpoint of the non-coronary sinus, spread apart and photographed by a high-resolution digital camera. After calibration and picture resizing, the software AutoCAD 2004 was used to identify and measure all the elements of the interleaflets triangles and of the aortic root that were objects of our analysis. Multiple comparisons were performed with one-way analysis of variance for continuous data and with Kruskal-Wallis analysis for non-continuous data. Linear regression and Pearson's product correlation were used to correlate root element dimensions when appropriate. Student's t-test was used to compare means for unpaired data. Heron's formula was applied to estimate the functional aortic annular diameters. RESULTS: The non coronary-left coronary interleaflets triangles were larger, followed by inter-coronary and right-non-coronary ones. The apical angle is <60° and its standard deviation can be considered an asymmetry index. The sinu-tubular junction was shown to be 10% larger than the virtual basal ring (VBR). The mathematical relationship between the haemodynamic ventriculo-arterial junction and the VBR calculated by linear regression and expressed in terms of the diameter was: haemodynamic ventriculo-arterial junction = 2.29 VBR (diameter) + 47. DISCUSSION: Conservative aortic surgery is based on a better understanding of aortic root anatomy and physiology. The relationships among its elements are of paramount importance during aortic valve repair/sparing procedures and they can be useful also in echocardiographic analysis and in computed tomography reconstruction.

In vitro assessment of mitral valve function in cyclically pressurized porcine hearts.

Recent approaches to the in vitro experimental study of cardiac fluid mechanics involve the use of whole biological structures to investigate in the lab novel therapeutic approaches for the treatment of heart pathologies. To enhance reliability and repeatability, the influence of the actuation strategy of the experimental apparatuses on the biomechanics of biological structures needs to be assessed. Using echography and intracardiac high-speed imaging, we compared the mitral valve (MV) anatomo-functional features (coaptation areas/lengths, papillary muscles-valvular plane distances) in two passive-beating-heart mock loops with internal (IPML) or external (EPML) pressurization of the ventricular chamber. Both apparatuses showed fluid dynamic conditions that closely resembled the physiology. The MVs analyzed in the EPML presented coaptation areas and lengths that were systematically higher, and exhibited greater variability from early-to peak-systole, as compared to those in the IPML. Moreover, in the EPML, the MV leaflets exhibited a convexity with high curvature toward the atrium. With the IPML, MV coaptation lengths ranged similar to available clinical data and the papillary muscles-valve plane distances were more stable throughout systole. In conclusion, both the apparatuses allow for reproducing in vitro the left heart hemodynamics, in terms of flow rates and pressures, with proper mitral valve continence. Results suggest that the IPML is more suitable for replicating the physiological MV functioning, while the EPML may have more potential as a model for the study of MV pathologies.

Assessment of an aortosaphenous vein graft anastomotic device in coronary surgery: clinical experience and early angiographic results.

BACKGROUND: Until now technologic evolution in coronary bypass surgery has focused on extracorporeal circulation, on operation without extracorporeal circulation, and on the exposure of the operative site. Recently a one-shot anastomotic device for the proximal anastomosis in coronary surgery was developed. We investigated whether the use of the aortic connector system (ACS) could facilitate the creation of aortosaphenous vein graft anastomoses in myocardial revascularization. METHODS: From November 2000, 40 ACS devices were used in 36 consecutive patients (mean age 70.7 +/- 8.9 years); 12 patients (33.3%) underwent surgery on pump and 24 patients (66.6%) off pump; 50 distal anastomoses were performed. In all cases the connection with the ascending aorta was created before the distal anastomoses because of the necessity to slide the saphenous vein graft (SVG) over the vein transfer sheath. Intraoperative graft function was tested measuring blood flow by Doppler analysis. Postoperative evaluation of the anastomotic patency was carried out by early angiography in 34 patients (94.7%) but was excluded in 5 patients (5.3%) with extensive extracardiac vascular occlusive disease. RESULTS: Of 38 AC (95%) evaluated, 36 (94.7%) functioned properly. The end-to-side proximal anastomosis without aortic clamping is instantaneous, the quality of anastomoses was highly rated, no additional stitches were required, and all coronary arteries could be reached. Intraoperative quantity flow was measured by Doppler analysis and all but one showed good flow. Early postoperative angiography demonstrated good patency of the grafts in all cases but 2 (5.3%). At 1-year follow-up, 1 patient died of stroke; all other patients remained free of symptoms and no reoperation was required. CONCLUSIONS: The use of ACS makes end-to-side anastomosis rapid, effective, and reproducible while eliminating aortic cross clamping; it opens a new era in beating or nonbeating coronary surgery. Long-term results are mandatory to confirm our favorable preliminary results.

Effects of heart rate on phasic Y-graft blood flow and flow reserve in patients with complete arterial myocardial revascularizaton: an intravascular Doppler catheter study.

OBJECTIVE: It is not well established whether the blood flow of arterial composite Y-grafts can efficiently respond to the flow demand of the coronary system early postoperatively. The aim of this study was to evaluate if soon after the operation, arterial composite Y-grafts can increase blood flow in response to an increase in myocardial oxygen consumption (MVO2). METHODS: Twenty-seven patients who received complete arterial myocardial revascularization using the left internal thoracic artery (LITA) and the radial artery (RA) as composite Y-graft gave their consent to a pre-discharge coronary angiography and intravascular flow velocity measurements using a Doppler guide wire. Flow measurements were performed in the LITA main stem, the distal LITA and the RA, both at rest and during atrial pacing at the 85% of the patient age-predicted maximum. The heart rate-systolic blood pressure product was considered as an indirect index of MVO2. Hyperemic flow was determined after injection of adenosine. The flow reserve (FR) was defined as the ratio of blood flow during maximal hyperemia (Qmax) to baseline flow (Qbasal). RESULTS: Atrial pacing increased MVO2 significantly (P<0.000). None of the patients developed ischemic S-T segment modifications or complained of chest pain. Q(basal) increased significantly in the LITA main stem (P=0.001), distal LITA (P=0.041) and RA (P=0.004) while Qmax did not change significantly. As a consequence, the FR decreased in the LITA main stem (P=0.002), distal LITA (P<0.000) and RA (P<0.000) but was not completely exhausted. CONCLUSIONS: Soon after the operation, arterial composite Y-grafts can significantly increase blood flow in response to conditions of increased MVO2, keeping normal the myocardial O2 supply-to-demand ratio.

Is it better to use the radial artery as a composite graft? Clinical and angiographic results of aorto-coronary versus Y-graft.

OBJECTIVE: We sought to evaluate whether the radial artery (RA) provides the same clinical and angiographic results when proximally anastomosed to the aorta or to the left internal thoracic artery (ITA) as a composite Y-graft. METHODS: From February 1999 to December 2002, 512 patients underwent myocardial revascularization using the RA, the left ITA and, when required, the saphenous vein. According to the surgeons' preference the RA was proximally anastomosed to the aorta [336 patients (65.6%), Ao-Cor group] or to the left ITA as a composite Y-graft [176 patients (34.4%), Y-graft group]. There was a significant prevalence of three-vessel disease (86.8 versus 73.2%, (P = 0.000) and elderly age (60+/-9 versus 58+/-8 years, (P = 0.014) in the Y-graft group. RESULTS: Patients in Y-graft group had longer aortic cross clamp time (P = 0.001), more bypass grafts per patient (P < or = 0.001) more arterial bypass grafts per patient (P < or = 0.001) and more bypass grafts per patient with the RA (P < or = 0.001). There were no differences in terms of perioperative outcome. Mean follow-up time was 27.1+/-11.7 months in 322/333 (96.7%) patients of the Ao-Cor group and 14.9+/-10.2 in 165/172 (95.9%) patients of the Y-graft group. There was no difference in terms of overall survival (P = 0.75) cardiac event-free survival (P = 0.65) RA patency rate at postoperative angiography (P = 0.59) and during follow-up (P = 0.93). A preoperative coronary artery stenosis < or = 70% was related with competitive flow (P = 0.000) at postoperative angiography and with RA occlusion (P = 0.001) at follow-up angiography. CONCLUSIONS: The RA provides the same clinical and angiographic results both as aorto-coronary and composite Y-graft with the left ITA. When the RA is used as Y-graft the procedure is more technically demanding and a greater number of distal coronary anastomoses is possible. RA grafts to targets with stenosis < or = 70% appear to be at risk of failure.

Analysis of Y-graft blood flow and flow reserve in conditions of increased myocardial oxygen consumption.

BACKGROUND: It is not well established whether early following surgery the blood flow of arterial composite Y-grafts may efficiently meet the flow demand of the coronary system. The aim of this study was to evaluate whether early after surgery arterial composite Y-grafts may increase the blood flow in response to an increase in myocardial oxygen consumption (MVO2). METHODS: Twenty-seven patients who received complete arterial myocardial revascularization using the left internal thoracic artery (LITA) and the radial artery (RA) as composite Y-graft gave their consent to a pre-discharge coronary angiography and intravascular flow velocity measurements using a Doppler guidewire. Flow measurements were performed in the LITA main stem, the distal LITA and the RA, both at rest and during atrial pacing at 85% of the patient age-predicted maximum heart rate. The heart rate-systolic blood pressure product was considered as an indirect index of MVO2. Hyperemic flow was determined after injection of adenosine. The flow reserve was defined as the ratio of blood flow during maximal hyperemia (Qmax) to baseline flow (Qbasal). RESULTS: Atrial pacing significantly increased MVO2 (p < 0.000). None of the patients developed ischemic ST-segment modifications or complained of chest pain. Qbasal increased significantly in the LITA main stem (p = 0.001), distal LITA (p = 0.041) and RA (p = 0.004) while Qmax did not change significantly. As a consequence the flow reserve decreased in the LITA main stem (p = 0.002), distal LITA (p = 0.000) and RA (p = 0.000) but was not completely exhausted. CONCLUSIONS: Early after surgery arterial composite Y-grafts may significantly increase blood flow in response to conditions of increased MVO2 and maintain a normal myocardial oxygen supply-to-demand ratio.

[Acute embolic myocardial infarction complicating bioprosthetic stentless aortic valve endocarditis]. / Infarto miocardico acuto embolico in corso di endocardite su bioprotesi valvolare aortica stentless.

We describe the case of bioprosthetic stentless aortic valve endocarditis due to Staphylococcus epidermidis in a female patient, who previously underwent mitral and aortic valve replacement: she presented left main coronary artery occlusion due to septic embolus with subsequent myocardial infarction complicated by cardiogenic shock. We discuss the therapeutic strategies, both medical and interventional, and the surgical options.

Aortic valve repair: a ten-year single-centre experience†.

OBJECTIVES: Aortic valvuloplasty could represent an alternative to valve replacement resulting in optimal haemodynamic conditions, avoiding anticoagulation and allowing, in young people, normal aortic annulus growth. We analysed our results of aortic valve repair for incompetence due to leaflets and root pathology. METHODS: From January 2003 to January 2013, 235 patients affected by aortic valve regurgitation, pure or associated with aortic dilatation, were treated with a combination of the principal leaflet repair techniques and, when necessary, sparing procedures. Of these patients, 218 were considered eligible in this study. All of them were submitted to pre- and postoperative transthoracic echocardiography and pre- and post-repair transoesophageal echocardiography. Follow-up was achieved with periodic echocardiograms and clinical evaluations. RESULTS: Eight patients (3.40%) died before discharge. Median clinical and echocardiographic follow-up for all patients was 2.94 (1.41-5.41) years. Mean cross-clamping time was 101.94 ± 40.22 min and mean hospital stay was 10 ± 6.69 days. Kaplan-Meier freedom from aortic regurgitation >2 and freedom from aortic valve replacement were, respectively, 92.9 ± 2.8 and 94.5 ± 2.5% at 9.24 years: 6 patients (2.75%) were reoperated on with aortic valve replacement for severe aortic regurgitation. We also observed a good effect of aortic surgery on the left ventricle: the end-diastolic volume decreased from 137.89 ± 50.23 ml in the preop to 105.17 ± 31.19 ml at follow-up. CONCLUSIONS: Aortic valve leaflet repair seems to be a good and feasible option for selected patients, both alone or associated with an aortic sparing technique concerning long-term results.

Minimally invasive cardiac surgery-coronary artery bypass graft.

Coronary artery bypass graft (CABG) is among the most common operations performed in the world. Different surgical strategies can be used with different invasiveness. This paper describes a recent development of the technique that merges the advantages resulting from both the adoption of an 'off-pump no-touch aorta operation' and a 'complete arterial revascularization through a left minithoracotomy' in a single procedure. This operation is currently known with the acronym MICS (minimally invasive cardiac surgery)-CABG (minimally invasive cardiac surgery). It is an off-pump operation performed through a minithoracotomy in the fourth or fifth left intercostal space across the midclavicular line. The left internal thoracic artery (LITA) is harvested under direct vision using a special rib-retractor with multiple interchangeable thoracotomy blades, including blades to use with lift systems for proximal artery harvesting, while the right radial artery (RA) is harvested endoscopically. A Y-connection is made between the two arteries. The LITA is used to bypass the left anterior descending coronary artery, while the right RA is used on the obtuse marginal branches and/or the posterior descending coronary artery. A special coronary stabilizer and a heart positioner with a shaft for remote thoracic insertion are needed.