Implementation of Endoscopic Minimally Invasive Mitral Valve Replacement Surgery With Automated Suturing Technology

In the evolving landscape of cardiac surgery, this article explores the potential of minimally invasive mitral valve replacement procedures as a viable alternative to conventional surgical techniques. Leveraging advancements in automated suturing devices and video endoscopy, our work aims to demonstrate that minimally invasive approaches can be applied across a broad spectrum of surgical scenarios. Herein we highlight preoperative diagnostics and operative techniques, with a focus on infra-axillary anterolateral minithoracotomy as the access point. Our technique utilizes technology from LSI SOLUTIONS® (Victor, NY, USA), including the RAM® Device for automated suturing, which has an ergonomic design and safety features. The device's capabilities are further enhanced by the SEW-EASY® Device, the RAM® RING, and the COR-KNOT MINI® Device, which streamline suture management and securement. This work outlines how these technological advancements can mitigate concerns about technical complexity and learning curves, thereby encouraging wider adoption of minimally invasive techniques. Clinical benefits may include reduced surgical trauma, quicker recovery, and cost-effectiveness, making it a compelling option in an era of aggressively promoted transcatheter interventions.

Pacemaker implantation after concomitant tricuspid valve repair in patients undergoing minimally invasive mitral valve surgery: Results from the Mini-Mitral International Registry

Objective

Randomized evidence suggests a high risk of pacemaker implantation for patients undergoing mitral valve (MV) surgery with concomitant tricuspid valve repair (cTVR). We investigated the impact of cTVR on outcomes in the Mini-Mitral International Registry.

Methods

From 2015 to 2021, 7513 patients underwent minimally invasive MV with or without cTVR in 17 international centers (MV: n = 5609, cTVR: n = 1113). Propensity matching generated 1110 well-balanced pairs. Multivariable analysis was applied.

Results

Patients with cTVR were older and had more comorbidities. Propensity matching eliminated most differences except for more TR in patients who underwent cTVR (77.2% vs 22.1% MV, P < .001). Mean matched age was 71 years, and 45% were male. European System for Cardiac Operative Risk Evaluation II was still 2.68% (interquartile range [IQR], 0.80-2.63) vs 1.9% (IQR, 1.12-3.9) in matched MV (P < .001). MV replacement (30%) and atrial fibrillation surgery (32%) were similar in both groups. Cardiopulmonary bypass (161 minutes [IQR, 133-203] vs MV: 130 minutes [IQR, 103-166]; P < .001) and crossclamp times (93 minutes [IQR, 66-123] vs MV: 83 minutes [IQR, 64-107]; P < .001) were longer with cTVR. Although in-hospital mortality was similar (cTVR: 3.3% vs MV: 2.2%; P = .5), postoperative pacemaker implantations (9% vs MV: 5.8%; P = .02), low cardiac output syndrome (7.7% vs MV: 4.4%; P = .02), and acute kidney injury (13.8% vs MV: 10%; P = .01) were more frequent with cTVR. cTVR eliminated relevant TR in most patients (greater-than-moderate TR: 6.8%). Multivariable analysis identified MV replacement, atrial fibrillation, and cTVR as risk factors of postoperative pacemaker implantation.

Conclusions

cTVR in minimally invasive MV surgery is an independent risk factor for pacemaker implantation in this international registry. It is also associated with more bleeding, low output syndrome, and acute kidney injury. It remains unclear whether technical or patient factors (or both) explain these differences.

Periostin is overexpressed, correlated with fibrosis and differs among grades of cardiomyocyte hypertrophy in myectomy tissue of patients with hypertrophic cardiomyopathy

Periostin, a secreted matricellular protein, has been implicated in cardiac extracellular matrix remodeling and fibrosis. Evidence suggest that periostin stimulates cardiomyocyte hypertrophy. The current study aims to investigate the extent of periostin expression in patients with advanced Hypertrophic Cardiomyopathy (HCM) and its correlation with fibrosis and hallmark histopathological features of the disease. Interventricular septal tissue from thirty-nine HCM patients who underwent myectomy and five controls who died from non-cardiac causes was obtained. Staining with Masson's Trichrome and immunohistochemistry were used to localize fibrosis and periostin respectively. The extent of fibrosis and the expression of periostin were defined as the stained percentage of total tissue area using digital pathology software. Periostin expression was higher in HCM patients compared to controls (p<0.0001), positively correlated with the extent of fibrosis (r = 0.82, p<0.001), positively correlated with maximal interventricular septal thickness (Rho = 0.33, p = 0.04) and negatively correlated with LVEF (r = -0.416, p = 0.009). Periostin was approximately co-localized with fibrosis. Mean periostin expression was lower in patients with mild grade cardiomyocyte hypertrophy compared to those with moderate grade (p = 0.049) and lower in patients with mild grade replacement fibrosis compared to moderate grade (p = 0.036). In conclusion, periostin is overexpressed in advanced HCM, correlated with fibrosis and possibly related to cardiomyocyte hypertrophy.

Neurological outcomes in minimally invasive mitral valve surgery: risk factors analysis from the Mini-Mitral International Registry

OBJECTIVES

The aim of this study was to examine the incidence and predictors of stroke after minimally invasive mitral valve surgery (mini-MVS) and to assess the role of preoperative CT scan on surgical management and neurological outcomes in the large cohort of Mini-Mitral International Registry.

METHODS

Clinical, operative and in-hospital outcomes in patients undergoing mini-MVS between 2015 and 2021 were collected. Univariable and multivariable analyses were used to identify predictors of stroke. Finally, the impact of preoperative CT scan on surgical management and neurological outcomes was assessed.

RESULTS

Data from 7343 patients were collected. The incidence of stroke was 1.3% (n = 95/7343). Stroke was associated with higher in-hospital mortality (11.6% vs 1.5%, P < 0.001) and longer intubation time, ICU and hospital stay (median 26 vs 7 h, 120 vs 24 h and 14 vs 8 days, respectively). On multivariable analysis, age (odds ratio 1.039, 95% confidence interval 1.019-1.060, P < 0.001) and mitral valve replacement (odds ratio 2.167, 95% confidence interval 1.401-3.354, P < 0.001) emerged as independent predictors of stroke. Preoperative CT scan was made in 31.1% of cases. These patients had a higher risk profile and EuroSCORE II (median 1.58 vs 1.1, P < 0.001). CT scan influenced the choice of cannulation site, being ascending aorta (18.5% vs 0.5%, P < 0.001) more frequent in the CT group and femoral artery more frequent in the no CT group (97.8% vs 79.7%, P < 0.001). No difference was found in the incidence of postoperative stroke (CT group 1.5, no CT group 1.4%, P = 0.7).

CONCLUSIONS

Mini-MVS is associated with a low incidence of stroke, but when it occurs it has an ominous impact on mortality. Preoperative CT scan affected surgical cannulation strategy but did not led to improved neurological outcomes.

Acute mitral regurgitation with and without acute heart failure

Acute severe mitral regurgitation (MR) is rare, but often leads to cardiogenic shock, pulmonary edema, or both. Most common causes of acute severe MR are chordae tendineae (CT) rupture, papillary muscle (PM) rupture, and infective endocarditis (IE). Mild to moderate MR is often seen in patients with acute myocardial infarction (AMI). CT rupture in patients with floppy mitral valve/mitral valve prolapse is the most common etiology of acute severe MR today. In IE, native or prosthetic valve damage can occur (leaflet perforation, ring detachment, other), as well as CT or PM rupture. Since the introduction of percutaneous revascularization in AMI, the incidence of PM rupture has substantially declined. In acute severe MR, the hemodynamic effects of the large regurgitant volume into the left atrium (LA) during left ventricular (LV) systole, and in turn back into the LV during diastole, are profound as the LV and LA have not had time to adapt to this additional volume. A rapid, but comprehensive evaluation of the patient with acute severe MR is essential in order to define the underline cause and apply appropriate management. Echocardiography with Doppler provides vital information related to the underlying pathology. Coronary arteriography should be performed in patients with an AMI to define coronary anatomy and need for revascularization. In acute severe MR, medical therapy should be used to stabilize the patient before intervention (surgery, transcatheter); mechanical support is often required. Diagnostic and therapeutic steps should be individualized, and a multi-disciplinary team approach should be utilized.

Aortic Cross-Clamp Time Correlates with Mortality in the Mini-Mitral International Registry

OBJECTIVES

Minimally invasive access has become the preferred choice in mitral and/or tricuspid valve surgery (MVR±TVR). Reported outcomes are at least similar to classic sternotomy although aortic cross-clamp times are usually longer.

METHODS

We analyzed the largest registry of MVR±TVR patients (MMIR) for the relationship between aortic cross-clamp times, mortality and other outcomes. From 2015-2021, 7,513 consecutive patients underwent mini-MVR±TVR in 17 international Heart-Valve-Centres. Data were collected according to MVARC definitions and 6878 patients with one cross-clamp period were analysed. Uni- and multivariable regression analyses were used to assess outcomes in relation to aortic cross-clamp times.

RESULTS

Median age was 65 years (57% male). Median EuroSCORE II was 1.3% (IQR: 0.80-2.63). Minimally invasive access was either by direct vision (28%), video-assisted (41%) or totally endoscopic/robotic (31%). Femoral cannulation was used in 93%. Three quarters were repairs with 17% additional TVR and 19% AF-ablation. Cardiopulmonary bypass and cross-clamp times were 135 min (IQR : 107-173) and 85 min (IQR : 64-111), respectively. Postoperative events were death (1.6%), stroke (1.2%), bleeding requiring revision (6%), low cardiac output syndrome (3.5%) and acute kidney injury (6.2%, mainly stage I). Statistical analyses identified significant associations between cross-clamp time and mortality, low cardiac output syndrome and acute kidney injury (all p < 0.001). Age, low ejection fraction and emergent surgery were risk factors, but variables of "increased complexity" (redo, endocarditis, concomitant procedures) were not.

CONCLUSIONS

Aortic cross-clamp time is associated with mortality as well as postoperatively impaired cardiac and renal function. Thus, implementing measures to reduce cross-clamp time may improve outcomes.

Risk-related clinical outcomes after minimally invasive mitral valve surgery: insights from the mini-mitral international registry (MMIR)

OBJECTIVE

With the popularization of catheter-based mitral valve procedures, evaluating risk-specific differentiated clinical outcomes after contemporary mitral valve surgery is crucial. In this study, we assessed the operative results of minimally invasive mitral valve operations across different patient risk profiles and evaluated the value of EuroSCORE II predicted risk of mortality model for risk prediction, in the large cohort of Mini-Mitral International Registry (MMIR).

METHODS

The MMIR database was used to analyze mini-mitral operations between 2015 and 2021. Patients were categorized as low- (<4%), intermediate- (4% to < 8%), high- (8% to < 12%) and extreme risk (≥12%) according to EuroSCORE II. The observed to expected (O: E) mortality ratio was calculated for each risk group.

RESULTS

A total of 6541 patients were included in the analysis. Of those, 5546 (84.8%) were classified as low risk, 615 (9.4%) as intermediate risk, 191 (2.9%) as high risk and 189 (2.9%) as extreme risk. Overall operative mortality and stroke rates were 1.7% and 1.4%, respectively, and were significantly associated with patient's risk. The observed mortality was significantly lower than expected -according to the EuroSCORE II- in all risk categories (O: E ratio < 1).

CONCLUSIONS

The present study provides an international contemporary benchmark for operative outcomes after minimally invasive mitral surgery. Operative results were excellent in low-, intermediate- and high risk patients, but were less satisfactory in extreme risk. The EuroSCORE II model overestimated the in-hospital mortality. We believe findings from the MMIR may assist surgeons and cardiologists in clinical decision-making and treatment allocation for patients with mitral valve disease.

Totally endoscopic aortic valve replacement with concomitant trans-aortic mitral valve repair for mitral regurgitation

Background

Minimally invasive aortic valve procedures through a hemi-sternotomy or a right anterior mini-thoracotomy have gained popularity over the last several years. Totally endoscopic aortic valve replacement (TEAVR) is an innovative and a less invasive (incision-wise) surgical aortic valve replacement technique. The operative steps of TEAVR have been reported previously from our group. Mitral regurgitation (MR) frequently accompanies aortic valve disease that at times may also require repair. Totally endoscopic surgery in such cases has not been tested.

Presentation of the technique

We present a surgical technique for a totally endoscopic approach to aortic valve replacement and concomitant mitral valve repair for primary and secondary MR. An aortotomy incision was used avoiding an atriotomy, which results in an increase in cross-clamp (XC) and cardiopulmonary bypass (CPB) times that could be associated with higher mortality and morbidity. Neochords (artificial chordae tendineae) were used for primary MR and an edge-to-edge approach for secondary MR.

Conclusion

TEAVR and concomitant mitral valve repair can be performed successfully with reasonable XC and CPB times with excellent short-term results.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-021-01694-6.

Routine histopathology of septal myectomy for hypertrophic obstructive cardiomyopathy in a greek cohort

Hypertrophic cardiomyopathy (HCM) is a diverse inherited disease affecting 1 in 500 individuals irrespective of gender and ethnicity. A fraction of HCM patients will eventually develop drug refractory dynamic obstruction of the left ventricular outflow tract. For such patients, septal myectomy is the procedure of choice to alleviate their symptoms and improve their quality of life. The current histopathological study, the first from the Greek region, aims to examine the hallmark histopathological characteristics of Hypertrophic Obstructive Cardiomyopathy in a population of patients undergoing septal myectomy at a single center over a ten year period. Medical records and histopathology specimens of thirty nine (n=39) patients were evaluated. The sample comprised 22 males (56.4%) and 17 females (43.6%). Mean patient age at myectomy was 53.9±16.7 years, ranging from 12 to 79 years. Maximal IVS thickness on echocardiography was available for 35 patients with a median value of 2.08cm. Peak resting LVOT Pressure Gradient was available for 33 patients with a mean value of 104.88±44.20 mmHg. Central tendency of each histopathological attribute expressed as the median value was: moderate for myocyte hypertrophy, mild for cytoplasmic vacuolization, moderate for subendocardial fibrosis, moderate for interstitial fibrosis, mild for replacement fibrosis, moderate for myofibrillar disarray and mild for capillary stenosis. Myocyte hypertrophy, present in all specimens, was positively correlated with maximal IVS thickness (tau-b=0.43, p=0.002). Replacement fibrosis was positively correlated with the grade of microvascular stenosis (tau-b=0.45, p=0.004). LVEF was negatively correlated with the grade of interstitial fibrosis (tau-b=-0.43, p=0.035) and with the extent of myocardial fiber disarray (tau-b=-0.42, p=0.034). Histopathological attributes were not correlated with patient gender or age thus proving that HCM has a histological phenotype unique to each patient, mainly depending on each specific sarcomeric mutation.

Mitral commissural prolapse

Mitral commissural prolapse or flail, either isolated or combined with more extensive degenerative valve disease, imposes several challenges both on its diagnosis and management while being a risk factor for valve reoperation after mitral valve repair. Accurate identification of the prolapsing segment is often not feasible with transthoracic 2D echocardiography, with transesophageal 3D imaging then required for correct diagnosis and surgical planning. Various surgical techniques employed alone or in combination have yielded good results in the repair of commissural prolapse. Herein, we analyze the specific characteristics of commissural disease focusing our attention on 2D and 3D echocardiographic findings and we briefly comment on techniques employed for surgical correction of the disease.

Preoperative determination of artificial chordae tendineae length by transoesophageal echocardiography in totally endoscopic mitral valve repair

OBJECTIVES

Artificial chordae tendineae are widely used for surgical repair in patients with mitral regurgitation due to floppy mitral valve/mitral valve prolapse. Expanded polytetrafluoroethylene has been used to construct these artificial chordae; however, the determination of the optimal length of the chordae prior to surgery has been an issue. For this reason, such a method was developed and the results of its use are presented.

METHODS

Forty-seven consecutive patients with significant mitral regurgitation due to floppy mitral valve/mitral valve prolapse who underwent totally endoscopic mitral valve surgery were studied. The chordae length was predetermined using transoesophageal echocardiography. The length between the top of the fibrous body of the papillary muscle and the coaptation line of the 2 leaflets of the mitral valve was measured and used to define the length of the chordae to be used for repair. Then under stereoscopic vision, a total endoscopic mitral valve repair was performed.

RESULTS

The predicted mean length of chordal loops was 19.76 ± 0.71 mm (median 20, range 16-28) and the actual mean length of chordal loops used was 19.68 ± 0.74 mm (median 20, range 16-26) demonstrating an excellent correlation between the two (r = 0.959). The mean number of chordae loops used per patient was 5.12 ± 0.62 (median 4, range 2-12). All patients at the time of discharge had no or trivial mitral regurgitation on transoesophageal echocardiography.

CONCLUSIONS

The chordae length used for mitral valve repair can be determined prior to surgery using transoesophageal echocardiography with a high degree of accuracy. Further, total endoscopic repair in this group of patients provides excellent results. For these reasons, it is expected that this method will replace most traditional approaches to cardiac surgeries in the years to come.

Totally endoscopic aortic valve replacement with stented biological and mechanical aortic prostheses

Background

Endoscopic mitral valve surgery has become the gold standard of care in many expert centres around the globe. The aortic valve has not met the same popularity mainly due to the very confined space in the aortic root, and to the close proximity with the sternum which restricts the movement of the endoscopic instruments. When endoscopic aortic valve replacement is practiced in expert centres, is usually performed with the use of sutureless bioprostheses. We hereby present our experience of totally endoscopic aortic valve replacement (TEAVR) with conventional mechanical and biological prostheses.

Methods

Since January 2019, fifty-two consecutive patients with significant aortic stenosis and/or aortic regurgitation, who were operated with TEAVR with conventional prostheses were studied. 7,69% of the cases were REDOs. The prostheses used were either stented bovine pericardial in 84,6% of the patients and bileaflet mechanical in 15,4%. The operations were performed through a 3 to 4 cm working incision in the 3rd intercostal space (ICS) right parasternally (where an extra small soft tissue protector was deployed), a 10 mm port for the 3D, 30°, endoscope, and a 5 mm port for the left atrial vent. On full cardiopulmonary bypass, the heart was arrested with cardioplegia which was administered either in the aortic root or directly in the coronary ostia. A transverse aortotomy was performed 3 cm above the right coronary ostium. The native valve (tricuspid or bicuspid) was excised, the annulus was sized and the prostheses were inserted using twelve to fifteen annular sutures who were secured using an automated suture-fastening device. In order to facilitate exposure in the aortic root, a metal self-expandable net was used.

Results

The average age of the patients treated was 68,3 years (range 36–81, median 72). The mean EuroSCORE2 was 3,22 (0,9–12,01, SEM:0,71). The mean size of the prostheses inserted was 23,72 mm (21–27, median 23) and the mean postoperative peak gradient was 12,15 (5–19, SEM: 1,00). Mean cross clamp and CPB times were 75,38 min (SEM:5,87) and 116,30 (SEM:8,63). There was no case of paravalvular leak or pacemaker insertion. There was no mortality in this cohort of patients. There was one case of cerebrovascular accident.

Conclusions

TEAVR can be performed safely with conventional aortic prostheses. There are several advantages of the technique over the other aortic valve replacing approaches. Over the other surgical techniques has the advantage of not fracturing the sternum or spreading or dislodging the ribs and increased patient satisfaction. Over the TAVI has the advantages of fully removing the diseased native valve, securing the prosthesis at the exact annular level without any paravalvular leaks or need for pacemaker insertion and the ability of using mechanical prostheses. The main disadvantages of the technique are the relatively prolonged cross clamp and CPB times and the steep learning curve.

TEAVR

Funding Acknowledgement

Type of funding source: None

P6489Preoperative determination of artificial chordae length by transesophageal echocardiography

Patients and methods

Twenty-one consecutive patients (7 females) underwent mitral valve repair with artificial chordae for significant mitral valve prolapse in our department during the last year. The median age of the patients was 62 y. (range 25 - 87) and the mean EuroSCORE II 3,36% (SD 4,61%). During the prep TOE we determined the predicted length of the required replacement chordae for the repair using mainly the 4 chamber view to calculate the distance between the tip of the papillary muscle and the coaptation point of the two leaflets and we subtracted 5mm which is the minimum of the desired coaptation length (top right part of the Figure). All the patients underwent totally endoscopic mitral repair through a 3 cm right periareolar incision. 14,3% of the patients had anterior leaflet (AML) prolapse, 23,8% bileaflet and 61,9% posterior (PML). The appropriate length of the required chordae was measured intraoperatively.

Results

We used on average 3 loops of artificial chordae size 23,3 mm (SD 1,15mm) to treat the AML prolapse, 5 loops size 23,2 mm (SD 2,28mm) to treat the bileaflet prolapse and 2,23 loops size 18mm (SD 2mm) to treat the PML prolapse (bottom part of the figure). The predicted size of the artificial chordae had a positive correlation to the length used (Pearson correlation, p<0,001) as demonstrated in the top left part of the Figure. An annuloplasty band was implanted to all the patients. All the patients had no mitral regurgitation in the postoperative TOE. The mean valve area was 3,54cm2 (SD 0,57) and the mean peak gradient 5,6 mmHg (SD 1,82). There was no mortality.

Chordae length predicted by echo

Conclusion

The length of artificial chordae can be predetermined with great accuracy with the use of TOE, making TOE an important tool not only for the determination of the mitral lesion and quality of the repair but also for the planning of the operation.

Mitral valve repair: moving towards a personalized ring

Background

Mitral valve repair with the use of an annuloplasty ring is the procedure of choice in patients with significant mitral regurgitation (MR) due to floppy mitral valve (FMV)/mitral valve prolapse (MVP). The mitral annular size, shape and motion may vary substantially among patients and thus, commercially available rings may not be suitable for each individual patient.

Methods

A “personalized ring” (PR) was easily constructed in the operating room using a Dacron sheet and titanium ligating clips to custom fit to each individual mitral annulus shape and size. There were 127 patients with severe MR due to FMV/MVP that underwent mitral valve repair surgery; 58 patients received a PR and 69 patients received a commercial Carpentier-Edwards Physio II ring. The patient records were retrospectively analysed.

Results

There were no surgical deaths. In-hospital length-of-stay and blood transfusions were not statistically different between the two groups. Mitral valve area was greater (p < 0.05) in the PR group (3.78 ± 0.22) compared to the Physio II ring group (3.13 ± 0.21). Mitral annular area changed from systole to diastole by 14.35% ± 3.28% in the PR group and did not change in the Physio II ring group (p < 0.05). Systolic anterior motion (SAM) of the mitral valve occurred in 2 patients with the Physio II ring and no patients with the PR. Up to 8 years follow-up, all patients in both groups were alive with NYHA functional class I-II symptoms and mild or less MR.

Conclusions

The PR is suitable for all patients with significant MR due to FMV/MVP who require MV repair. The precise fit of the PR to the mitral annulus better preserves valve area and sphincter function of the mitral annulus, prevents SAM and provides excellent short and long-term results.

Simultaneous implantation of MitraClip devices in a patient with severe mitral and tricuspid valve regurgitation

We present a case of an 84-year old patient with severe mitral and tricuspid regurgitation with a lot of cormobidities who underwent a simultaneous transfemoral (one approach) mitral and tricuspid valve repair using the MitraClip system.

Hospitalisations for heart failure predict mortality in pulmonary hypertension related to congenital heart disease

OBJECTIVE

Despite the progress in the management of patients with adult congenital heart disease (ACHD), a significant proportion of patients still develop pulmonary hypertension (PH). We aimed to highlight the rate of the complications in PH-ACHD and the predicting factors of cumulative mortality risk in this population.

METHODS

Data were obtained from the cohort of the national registry of ACHD in Greece from February 2012 until January 2018.

RESULTS

Overall, 65 patients receiving PH-specific therapy were included (mean age 46.1±14.4 years, 64.6% females). Heavily symptomatic (New York Heart Association (NYHA) class III/IV) were 53.8% of patients. The majority received monotherapy, while combination therapy was administered in 41.5% of patients. Cardiac arrhythmia was reported in 30.8%, endocarditis in 1.5%, stroke in 4.6%, pulmonary arterial thrombosis in 6.2%, haemoptysis in 3.1% and hospitalisation due to heart failure (HF) in 23.1%. Over a median follow-up of 3 years (range 1-6), 12 (18.5%) patients died. On univariate Cox regression analysis history of HF hospitalisation emerged as a strong predictor of mortality (HR 8.91, 95% CI 2.64 to 30.02, p<0.001), which remained significant after adjustment for age and for NYHA functional class.

CONCLUSIONS

Long-term complications are common among patients with PH-ACHD. Hospitalisations for HF predict mortality and should be considered in the risk stratification of this population.

Elevated plasma levels of miR-29a are associated with hemolysis in patients with hypertrophic cardiomyopathy

BACKGROUND

miR-29a is a small non-coding RNA that is known to repress collagen synthesis. Interestingly, elevated plasma miR-29a was reported to correlate with pronounced myocardial fibrosis in patients with hypertrophic cardiomyopathy. The objective of this study was to elucidate the origin of plasma miR-29a, and evaluate its significance as a biomarker.

METHODS

miR-29a expression was evaluated in plasma (n=50) and myocardial samples (n=4) from patients with hypertrophic cardiomyopathy using RT-qPCR.

RESULTS

Although miR-29a was highly expressed in the myocardium, miR-29a plasma levels did not show any correlation with serum troponin I levels (r_s=-0.12, p=0.43), and the heart does not release significant amounts of miR-29a into the circulation via exosome secretion. Conversely, miR-29a was present in red blood cells, and plasma levels correlated significantly with markers of hemolysis: lactic dehydrogenase (r_s=0.36, p=0.01) and the absorbance of oxyhemoglobin at 414nm (r_s=0.39, p=0.006). Furthermore, the association between serum haptoglobin and the maximal blood flow velocity in the left ventricle outflow tract (r_s=-0.42, p=0.008) indicated that intravascular hemolysis is a manifestation of the disease.

CONCLUSIONS

miR-29a is highly expressed in myocardial tissue from patients with hypertrophic cardiomyopathy. In contrast, plasma miR-29a is primarily of nonmyocardial origin and is correlated significantly with the extent of hemolysis observed in these patients.

Oesophageal perforation following perioperative transoesophageal echocardiography

Transoesophageal echocardiography (TOE) is being used more often by cardiothoracic anaesthetists for the perioperative management of cardiac problems. Reports of iatrogenic oesophageal perforation by instrumentation of the oesophagus are increasing. Although TOE is considered safe, it may be more risky during surgery, because the probe is passed and manipulated in an anaesthetized patient. It may be in place for several hours so the risk of mucosal pressure and thermal damage is increased. Patients on cardiopulmonary bypass are also fully anticoagulated. We describe a case of oesophageal perforation following insertion of the TOE probe in a patient with gross cardiomegaly. Oesophageal distortion by cardiac enlargement may increase the risk of oesophageal perforation. Difficulty in passage of the TOE probe should be regarded with suspicion and withdrawal should be contemplated because the symptoms of oesophageal perforation are often delayed and non-specific. Delay in investigation, diagnosis and treatment will increase morbidity and mortality.

Smooth muscle tumors of the gastrointestinal tract. A 10-year experience

Benign or malignant smooth muscle tumors of the gastrointestinal tract are uncommon. The diagnostic and therapeutic approaches vary depending on the histological behavior of these neoplasms. Between 1981 and 1991, 32 patients with gastrointestinal tumors were treated at the Department of Surgery of the University of Patras. There were 16 females and 16 males. The mean age at the time of diagnosis was 61.9 years (range 22-83 years). Eighty-one per cent of the tumors were discovered in asymptomatic patients by a variety of diagnostic studies. Fifty-six per cent of tumors were located in the stomach, 38% in the small intestine and 6% in the colon. Leiomyomas made up 71.8% of these tumors and were treated by conservative excision. The malignant smooth muscle tumors were treated by radical excision in four cases and conservative excision in one case. The 5-year survival rate was 85% for leiomyomas and 0% for malignant smooth muscle tumors. There is widespread agreement that wide resection of the lesion is the appropriate treatment for these tumors. The size and mitotic activity of these tumors remain the most important diagnostic parameters and prognostic factors.