Imaging of the Diaphragm Following Cardiac Surgery: Focus on Ultrasonographic Assessment.

Diaphragm dysfunction is a common complication following cardiac surgery. Its clinical impact is variable, ranging from the absence of symptoms to the acute respiratory failure. Post-operative diaphragm dysfunction may negatively affect patients' prognosis delaying the weaning from the mechanical ventilation (MV), extending the time of hospitalization and increasing mortality. Ultrasonography is a valid tool to evaluate diaphragmatic impairment in different settings, like the Intensive Care Unit, to predict successful weaning from the MV, and the Cardiovascular Rehabilitation Unit, to stratify patients in terms of risk of functional recovery failure. The aim of this review is to describe the pathophysiology of post-cardiac surgery diaphragm dysfunction, the techniques used for its diagnosis and the potential applications of diaphragm ultrasound.

Computing Methods for Composite Clinical Endpoints in Unprotected Left Main Coronary Artery Revascularization: A Post Hoc Analysis of the DELTA Registry.

OBJECTIVES: The study sought to investigate the impact of different computing methods for composite endpoints other than time-to-event (TTE) statistics in a large, multicenter registry of unprotected left main coronary artery (ULMCA) disease. BACKGROUND: TTE statistics for composite outcome measures used in ULMCA studies consider only the first event, and all the contributory outcomes are handled as if of equal importance. METHODS: The TTE, Andersen-Gill, win ratio (WR), competing risk, and weighted composite endpoint (WCE) computing methods were applied to ULMCA patients revascularized by percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) at 14 international centers. RESULTS: At a median follow-up of 1,295 days (interquartile range: 928 to 1,713 days), all analyses showed no difference in combinations of death, myocardial infarction, and cerebrovascular accident between PCI and CABG. When target vessel revascularization was incorporated in the composite endpoint, the TTE (p = 0.03), Andersen-Gill (p = 0.04), WR (p = 0.025), and competing risk (p < 0.001) computing methods showed CABG to be significantly superior to PCI in the analysis of 1,204 propensity-matched patients, whereas incorporating the clinical relevance of the component endpoints using WCE resulted in marked attenuation of the treatment effect of CABG, with loss of significance for the difference between revascularization strategies (p = 0.10). CONCLUSIONS: In a large study of ULMCA revascularization, incorporating the clinical relevance of the individual outcomes resulted in sensibly different findings as compared with the conventional TTE approach. In particular, using the WCE computing method, PCI and CABG were no longer significantly different with respect to the composite of death, myocardial infarction, cerebrovascular accident, or target vessel revascularization at a median of 3 years.

Incidence, management, and outcomes of cardiac tamponade during transcatheter aortic valve implantation: a single-center study.

OBJECTIVES: The aim of this study was to explore the incidence, causes, and outcomes of cardiac tamponade in patients undergoing transcatheter aortic valve implantation (TAVI). BACKGROUND: Use of TAVI is increasing, but the procedure is vulnerable to complications, given the cohort of patients. Cardiac tamponade is a possible complication, and there is a scarcity of data on the incidence and outcomes of cardiac tamponade during TAVI. METHODS: All patients who sustained cardiac tamponade during or post-TAVI between 2007 and 2012 were included in the study. RESULTS: Of 389 patients who underwent TAVI, 17 (4.3%) had cardiac tamponade. The mean age was 82.3 ± 3.7 years, and most were women (n = 12, 70.6%). Causes of cardiac tamponade were right ventricular perforation by temporary pacemaker (9 patients, 52.9%), annular rupture or aortic dissection (4 patients, 23.5%), and tear in the left ventricular free wall caused by Amplatz stiff wire or catheters (4 patients, 23.5%). Mortality occurred in 4 patients (23.5%), and all had tamponade caused by injury to the high-pressured left-sided circulation (left ventricle and aorta). Most patients (n = 14, 82.4%) sustained cardiac tamponade during the procedure-2 patients (11.7%) within 24 h, and 1 patient after 24 h. CONCLUSIONS: Cardiac tamponade during TAVI is not frequent but is associated with high mortality rates especially when left-sided structures are involved. Meticulous handling of the equipment and improvements in the safety of currently used devices could further reduce the occurrence of this complication.

Dynamic assessment of 'valvular reserve capacity' in patients with rheumatic mitral stenosis.

AIMS: Mitral stenosis (MS) may exhibit a dynamic valvular reserve. When resting gradients and systolic pulmonary pressure (sPAP) do not reflect the real severity of the disease, a dynamic evaluation becomes necessary. The aim of the study was to assess the clinical utility of exercise echocardiography in symptomatic patients with apparently subcritical MS. METHODS AND RESULTS: One hundred and thirty consecutive patients were referred for symptomatic MS. Patients with unimpressive resting MVA (>1-1.5 cm(2)) and mean PG (≥5-9 mmHg) underwent exercise echocardiography. Cardiac performance and mitral indices (MVA, peak/mean PG, sPAP) were measured. Exhaustion of valvular reserve capacity under exercise was defined as appearance of symptoms and sPAP > 60 mmHg. Forty-six patients (35%) (age: 53 ± 10 years; 74%, female) with resting MVA (1.2 ± 0.36 cm(2)), mean PG (6.8 ± 2.7 mmHg), and sPAP (38 ± 7 mmHg) inconsistent with symptoms underwent stress echocardiography. Exercise was stopped for dyspnoea (76%) or fatigue (24%). At peak workloads (57.2 ± 21.8 Watts), increased mean PG (17.2 ± 4.8 mmHg, P< 0.001) and sPAP (67.4 ± 11.4 mmHg; P< 0.0001) were observed, without change in MVA (1.25 ± 0.4 cm(2); P= n.s.). At univariate analysis, predictors of adaptation to exercise were age (-0.345; P = 0.024), mean PG (0.339; P= 0.023), and sPAP (0.354; P= 0.024); at multivariate analysis, best predictor was resting mean PG, although correlation was poor (-0.339; P= 0.015). CONCLUSION: In MS with limiting symptoms despite unimpressive findings at rest, valvular capacity exhaustion should be tested on a dynamic background, as no single resting index can predict potential haemodynamic adaptation to exercise. In such context, the contribution of exercise echocardiography remains extremely valuable.

Real-time three-dimensional transesophageal echocardiography for assessment of mitral valve functional anatomy in patients with prolapse-related regurgitation.

The aim of the study was to evaluate the additional diagnostic value of real-time 3-dimensional transesophageal echocardiography (RT3D-TEE) for surgically recognized mitral valve (MV) prolapse anatomy compared to 2-dimensional transthoracic echocardiography (2D-TTE), 2D-transesophageal echocardiography (2D-TEE), and real-time 3D-transthoracic echocardiography (RT3D-TTE). We preoperatively analyzed 222 consecutive patients undergoing repair for prolapse-related mitral regurgitation using RT3D-TEE, 2D-TEE, RT3D-TTE, and 2D-TTE. Multiplanar reconstruction was added to volume-rendered RT3D-TEE for quantitative prolapse recognition. The echocardiographic data were compared to the surgical findings. Per-patient analysis of RT3D-TEE identified prolapse in 204 patients more accurately (92%) than 2D-TEE (78%), RT3D-TTE (80%), and 2D-TTE (54%). Even among those 60 patients with complex prolapse (>1 segment localization or commissural lesions), RT3D-TEE correctly identified 58 (96.5%) compared to 42 (70%), 31 (52%), and 21 (35%) detected by 2D-TEE, RT3D-TTE, and 2D-TTE (p < 0.0001). Multiplanar reconstruction enabled RT3D-TEE to differentiate dominant (≥5-mm displacement) and secondary (2 to <5-mm displacement) prolapsed segments in agreement with surgically recognized dominant lesions (100%), but with a low predictive value (34%) for secondary lesions. In addition, owing to the identification of clefts and subclefts (indentations of MV tissue that extended ≥50% or <50% of the total leaflet height, respectively), RT3D-TEE accurately characterized the MV anatomy, including that which deviated from the standard nomenclature. In conclusion, RT3D-TEE provided more accurate mapping of MV prolapse than 2D imaging and RT3D-TTE, adding quantitative recognition of dominant and secondary lesions and MV anatomy details.

Complete left atrial ablation with bipolar radiofrequency.

OBJECTIVE: Despite its efficacy and swiftness, bipolar radiofrequency is generally not used on the left isthmus for concern of injuring a coronary branch. Incomplete lesion sets or use of an additional unipolar device are often considered. We report a technique to perform a full left lesion set involving the mitral line using a standard bipolar radiofrequency device. METHODS: An innovative complete left atrial lesion set was performed using only bipolar radiofrequency in 70 consecutive patients (study group). In 67/70 patients (96%) mitral valve disease was the main indication to surgery. Atrial fibrillation was permanent in 42 patients (60%), persistent in 25 (36%) and paroxysmal in three patients (4%). After beating-heart pulmonary vein isolation on-pump, the coronary-free area of the AV groove was marked epicardially by sticking a needle into the left atrial wall, behind the coronary sinus. The projection of the needle marker on the mitral annulus was then identified through the atriotomy and an endo-epicardial ablation was performed with the bipolar device involving the atrial wall, the coronary sinus, up to the annulus. The lesion set was then completed by connecting the encirclings and the left appendage, which was then sutured. Follow-up was 100% complete. Results were compared with those of a control group of 33 patients receiving bipolar radiofrequency left atrial ablations and a mitral connecting line with a second unipolar device. RESULTS: All patients survived. No major complication occurred. Haematoma of the AV groove was observed during retrograde cardioplegia in one case. No myocardial ischaemia or re-exploration for bleeding (median 325 cc, interquartile range 250-442) occurred. Two out of 70 patients required a permanent pacemaker for AV block. Freedom from atrial fibrillation was 84% (95% CI: 75%, 93%) at 6 months and 81% (95% CI: 70%, 93%) at 1 year. One patient had left flutter. Comparison with the control group did not show any difference in clinical outcomes, but revealed bipolar ablation to the mitral annulus to abate the per patient cost of the ablation devices (1245+/-50 euro vs 2403+/-17 euro; p<0.0001). CONCLUSIONS: Performing the mitral line with bipolar radiofrequency is safe and cost-effective. A complete left atrial ablation with a single bipolar radiofrequency device yields excellent clinical mid-term results.

Annular-to-leaflet mismatch and the need for reductive annuloplasty in patients undergoing mitral repair for chronic mitral regurgitation due to mitral valve prolapse.

Annular dilation is a common feature of chronic degenerative mitral regurgitation caused by leaflet prolapse. Accordingly, patients undergoing surgical repair usually undergo concomitant reductive annuloplasty to restore a normal annular-to-leaflet relation. With the evolution of transcatheter valve repair technologies, patient selection criteria for those who do not require annuloplasty are needed. A series of patients undergoing mitral repair was analyzed, and the role of annular-to-leaflet mismatch in identifying patients requiring reductive annuloplasty was explored. Preoperative data for 82 patients undergoing mitral repair with annuloplasty for degenerative mitral regurgitation were prospectively collected, including annular intercommissural (IC) and septolateral (SL) dimensions and heights of anterior (ALH) and posterior leaflets. An SL/ALH ratio >1.4 was used to define annular-to-leaflet mismatch. After mitral repair, the ratio between preoperative IC distance and the size of the implanted annular prosthesis (Seguin ring [SR], IC/SR <1.2) was used to identify patients for whom annuloplasty was nonreductive. All patients underwent successful mitral repair. Mean preoperative IC was 46 +/- 6 mm, SL was 42 +/- 5 mm, and ALH was 31 +/- 5 mm. Mean SR was 34 +/- 3 mm, with a mean IC/SR ratio of 1.34 +/- 0.14. Sixteen patients (19%) had an IC/SR ratio <1.2. IC/SR ratio <1.2 was predicted by a SL/ALH ratio < or =1.4 (p = 0.009). In conclusion, annular dilation is negligible in <20% of surgical candidates. In this subgroup, an isolated leaflet repair may be indicated. SL/ALH ratio is a good indicator of annular-to-leaflet mismatch and could be used as an adjunct to other methods of annular function assessment to select patients for ringless mitral repair.