Mitral valve repair using a semirigid ring: patient selection and early outcomes.

BACKGROUND: Commonly used complete mitral annuloplastic rings include saddle-shaped and semirigid rings, with no clear indication for either type. A semirigid ring may be preferred in patients whose native mitral saddle shape is well maintained. We present our experience of using semirigid rings for mitral valve repair. METHODS: We routinely measured the annular height-to-commissural width ratio by 3-dimensional transesophageal echocardiography prior to mitral repair. We generally chose a semirigid (Memo 3D) ring in patients whose annular height-to-commissural width ratio was normal (≥ 15%). The same semirigid ring with an additional chordal guiding system (Memo 3D ReChord) was selected for patients with anterior leaflet or bileaflet pathology. Over an 18-month period, 66 patients with severe degenerative (n = 60) or functional (n = 6) mitral regurgitation had Memo 3D (n = 32) or Memo 3D ReChord (n = 34) rings implanted. RESULTS: Postoperative 3-dimensional transesophageal echocardiography was completed in all patients (mean follow-up 7 ± 5 months). The majority of patients had no or mild residual mitral regurgitation; only two had moderate (2+) mitral regurgitation. There was no mortality at 30-days or on midterm follow-up. CONCLUSIONS: Our series represents the first Asian clinical experience using the Memo 3D ReChord ring. Although the long-term durability of mitral repair with this type of semirigid annuloplastic ring warrants further validation, our current clinical data are encouraging.

Automated quantification of mitral valve anatomy using anatomical intelligence in three-dimensional echocardiography.

BACKGROUND: Quantitative analysis of mitral valve morphology with three-dimensional (3D) transesophageal echocardiography (TEE) provides anatomic information that can assist clinical decision-making. However, routine use of mitral valve quantification has been hindered by tedious workflow and high operator-dependence. The purpose of this paper was to evaluate the feasibility, accuracy and efficiency of a novel computer-learning algorithm using anatomical intelligence in ultrasound (AIUS) to automatically detect and quantitatively assess the mitral valve anatomy. METHODS: A novice operator used AIUS to quantitatively assess mitral valve anatomy on the 3D TEE images of 55 patients (33 with mitral valve prolapse, 11 with functional mitral regurgitation, and 11 normal valves). The results were compared to that of manual mitral valve quantification by an experienced 3D echocardiographer and, in the 24 patients who underwent mitral valve repair, the surgical findings. Time consumption and reproducibility of AIUS were compared to the manual method. RESULTS: AIUS mitral valve quantification was feasible in 52 patients (95%). There were excellent agreements between AIUS and expert manual quantification for all mitral valve anatomic parameters (r=0.85-0.99, p<0.05). AIUS accurately classified surgically defined location of prolapse in 139 of 144 segments analyzed (97%). AIUS improved the intra- [intraclass-correlation coefficient (ICC)=0.91-0.99] and inter-observer (ICC=0.86-0.98) variability of novice users, surpassing the manual approach (intra-observer ICC=0.32-0.95; inter-observer ICC=0.45-0.93), yet requiring significantly less time (144±24s vs. 770±89s, p<0.0001). CONCLUSION: Anatomic intelligence in 3D TEE image can provide accurate, reproducible, and rapid quantification of the mitral valve anatomy.

A randomized controlled trial of adaptive support ventilation mode to wean patients after fast-track cardiac valvular surgery.

BACKGROUND: Adaptive support ventilation can speed weaning after coronary artery surgery compared with protocolized weaning using other modes. There are no data to support this mode of weaning after cardiac valvular surgery. Furthermore, control group weaning times have been long, suggesting that the results may reflect control group protocols that delay weaning rather than a real advantage of adaptive support ventilation. METHODS: Randomized (computer-generated sequence and sealed opaque envelopes), parallel-arm, unblinded trial of adaptive support ventilation versus physician-directed weaning after adult fast-track cardiac valvular surgery. The primary outcome was duration of mechanical ventilation. Patients aged 18 to 80 yr without significant renal, liver, or lung disease or severe impairment of left ventricular function undergoing uncomplicated elective valve surgery were eligible. Care was standardized, except postoperative ventilation. In the adaptive support ventilation group, target minute ventilation and inspired oxygen concentration were adjusted according to blood gases. A spontaneous breathing trial was carried out when the total inspiratory pressure of 15 cm H2O or less with positive end-expiratory pressure of 5 cm H2O. In the control group, the duty physician made all ventilatory decisions. RESULTS: Median duration of ventilation was statistically significantly shorter (P = 0.013) in the adaptive support ventilation group (205 [141 to 295] min, n = 30) than that in controls (342 [214 to 491] min, n = 31). Manual ventilator changes and alarms were less common in the adaptive support ventilation group, and arterial blood gas estimations were more common. CONCLUSION: Adaptive support ventilation reduces ventilation time by more than 2 h in patients who have undergone fast-track cardiac valvular surgery while reducing the number of manual ventilator changes and alarms.

Early risk stratification of patients with major trauma requiring massive blood transfusion.

BACKGROUND: There is limited evidence to guide the recognition of patients with massive, uncontrolled hemorrhage who require initiation of a massive transfusion (MT) protocol. OBJECTIVE: To risk stratify patients with major trauma and to predict need for MT. DESIGNS: Retrospective analysis of an administrative trauma database of major trauma patients. A REGIONAL TRAUMA CENTRE: A regional trauma centres in Hong Kong. PATIENTS: Patients with Injury Severity Score ≥ 9 and age ≥ 12 years were included. Burn patients, patients with known severe anemia and renal failure, or died within 24h were excluded. MAIN OUTCOME MEASURES: Delivery of ≥ 10 units of packed red blood cells (RBC) within 24h. RESULTS: Between 01/01/2001 and 30/06/2009, 1891 patients met the inclusion criteria. 92 patients required ≥ 10 units RBC within 24h. Seven variables which were easy to be measured in the ED and significantly predicted the need for MT are heart rate ≥ 120/min; systolic blood pressure ≤ 90 mm Hg; Glasgow coma scale ≤ 8; displaced pelvic fracture; CT scan or FAST positive for fluid; base deficit >5 mmol/L; hemoglobin ≤ 7 g/dL; and hemoglobin 7.1-10 g/dL. At a cut off of ≥ 6, the overall correct classification for predicting need for MT was 96.9%, with a sensitivity of 31.5% and specificity of 99.7%, and an incidence of MT of 82.9%. The area under the curve was 0.889. CONCLUSION: A prediction rule for determining an increased likelihood for the need for massive transfusion has been derived. This needs validation in an independent data set.

Randomized controlled trial comparing adaptive-support ventilation with pressure-regulated volume-controlled ventilation with automode in weaning patients after cardiac surgery.

BACKGROUND: Adaptive-support ventilation (ASV) is a minute ventilation-controlled mode governed by a closed-loop algorithm. With ASV, tidal volume and respiratory rate are automatically adjusted to minimize work of breathing. Studies indicate that ventilation in ASV enables more rapid weaning. The authors conducted a randomized controlled trial to determine whether ventilation in ASV results in a shorter time to extubation than pressure-regulated volume-controlled ventilation with automode (PRVCa) after cardiac surgery. METHODS: Fifty patients were randomly assigned to ASV or PRVCa after elective coronary artery bypass grafting. Respiratory weaning progressed through three phases: phase 1 (controlled ventilation), phase 2 (assisted ventilation), and phase 3 (T-piece trial), followed by extubation. The primary outcome was duration of intubation (sum of phases 1-3). Secondary outcomes were duration of mechanical ventilation (sum of phases 1 and 2), number of arterial blood gas samples, and manual ventilator setting changes made before extubation. RESULTS: Forty-eight patients completed the study. The median duration of intubation was significantly shorter in the ASV group than in the PRVCa group (300 [205-365] vs. 540 [462-580] min; P < 0.05). This difference was due to a reduction in the duration of mechanical ventilation (165 [120-195] vs. 480 [360-510] min; P < 0.05). There were no significant differences between the ASV and PRVCa groups in the number of arterial blood gas samples taken or manual ventilator setting changes made. CONCLUSIONS: ASV is associated with earlier extubation, without an increase in clinician intervention, when compared with PRVCa in patients undergoing uncomplicated cardiac surgery.