Superiority of magnesium cardioplegia in neonatal myocardial protection

Background. We have shown that magnesium can offset the detrimental effects of normocalcemic cardioplegia in hypoxic neonatal hearts. It is not known, however, whether magnesium offers any additional benefit when used in conjunction with hypocalcemic cardioplegia.

Methods. Twenty neonatal piglets underwent 60 minutes of ventilator hypoxia (FiO₂ 8% to 10%) followed by 20 minutes of normothermic ischemia on cardiopulmonary bypass (hypoxic-ischemic stress). They then underwent 70 minutes of multidose blood cardioplegic arrest. Five (Group 1), received a hypocalcemic (Ca⁺² 0.2 to 0.4 mM/L) cardiologic solution without magnesium, whereas in 10, magnesium was added at either a low dose (5 to 6 mEq/L, Group 2) or high dose (10 to 12 mEq/L, Group 3). In the last 5 (Group 4), magnesium (10 to 12 mEq/L) was added to a normocalcemic cardioplegic solution. Function was assessed using pressure volume loops and expressed as percentage of control.

Results. Compared to hypocalcemia cardioplegic solution without magnesium (Group 1), both high- and low-dose magnesium enrichment (Groups 2 and 3) improved myocardial protection resulting in complete return of systolic (40% vs 101% vs 102%) (p < 0.001 vs Groups 2 and 3) and global myocardial function (39% vs 102% vs 101%) (p < 0.001 vs Groups 2 and 3), and reduced diastolic stiffness (267% vs 158% vs 154%) (p < 0.001 vs Groups 2 and 3). Conversely, even high-dose magnesium supplementation could not offset the detrimental effects of normocalcemic cardioplegia resulting in depressed systolic (End Systolic Elastance [EES] 41% ± 1%) (p < 0.001 vs Groups 2 and 3) and global myocardial function (40% ± 1%) (p < 0.001 vs Groups 2 and 3), and a marked rise in diastolic stiffness (258% ± 5%) (p < 0.001 vs Groups 2 and 3). Hypocalcemic magnesium cardioplegia has now been used successfully in 247 adult and pediatric patients.

Conclusions. Magnesium enrichment of hypocalcemic cardioplegic solutions improves myocardial protection resulting in complete functional preservation. However, magnesium cannot prevent the detrimental effects of normocalcemic cardioplegia when the heart is severely stressed. This study, therefore, strongly supports using both a hypocalcemic cardioplegic solution and magnesium supplementation as their benefits are additive.     

Bicaval and standard techniques in orthotopic heart transplantation: medium-term experience in cardiac performance and survival.

OBJECTIVE: The aim of this study was to compare the medium-term results of right heart pressures, tricuspid valve dysfunction, overall cardiac performance, and survival between the bicaval and standard techniques. METHOD: Between 1991 and 1997, 201 heart transplantations were performed in our center. Right heart catheterization was performed up to 12 months after transplantation. Echocardiography was used to assess left ventricular and tricuspid valve function. RESULT: The standard technique was used in 105 cases, and the bicaval technique was used in 96 cases. There was no difference in the age, preoperative parameters, pulmonary hemodynamics, or ischemic time between the 2 groups. Right atrial pressure (4.3 +/- 4.0 mm Hg for the bicaval vs 10.9 +/- 4.8 mm Hg for standard technique) and mean pulmonary artery pressure (17.5 +/- 5.3 mm Hg and 22.5 +/- 5.2 mm Hg, respectively) were lower for the bicaval recipients up to 12 months after the operation (P =.001 and. 01, respectively). Left ventricular ejection fraction was higher for the recipients of the bicaval technique up to the most recent measurement (P =.005). The prevalence of moderate or severe tricuspid regurgitation was higher in the recipients of the standard technique up to the most recent measurement (28% vs 7%; P =.02). The actuarial survival at 1, 3, and 5 years was 74%, 70%, and 62% for the recipients of the standard technique versus 87%, 82%, and 81% for the recipients of the bicaval technique (P <.03, <.04, and <.02, respectively). CONCLUSION: The bicaval technique maintains good left ventricular function, lower incidence and severity of tricuspid valve dysfunction, and improved survival compared with the standard technique.     

The influence of histocompatibility on graft rejection and graft survival within a single center population of heart transplant recipients.

BACKGROUND: We report a consecutive single center series of 261 patients who received first orthotopic heart transplants from 1986 to 1997. The 1- and 5-year graft survivals were 78 and 68%. The influence of histocompatibility was investigated by comparing graft survival and numbers of treated rejection episodes with HLA-A, -B, and -DR mismatches over different time periods. FINDINGS: Recipients with six mismatches for HLA-A+-B+-DR combined (13.4%) had reduced survival at 7 years (47%) when compared with other recipients (64%). In the first year of transplant, recipients with four HLA-A+-B mismatches had significantly reduced actuarial graft survival (P=0.03) with the greatest influence apparent at 6 months [0-3 mismatches (n=193) 85% versus 4 mismatches (n=68) 69%; P=0.005, OR=2.1]. For 182 recipients with functioning hearts at 1 year, the number of rejection episodes treated within this time was strongly influenced by HLA-DR mismatch [0 DR mismatch (n=15) mean 1.2 rejection episodes versus 1 DR mismatch (n=76) mean 2.7 rejection episodes versus 2 DR mismatches (n=91) mean 3.8 rejection episodes: P=0.0002]. Of these 182 transplants, recipients who had more than four treated rejection episodes during the first year had a significantly reduced 7- year survival [<5 rejection episodes (n=133) 85% versus more than four rejection episodes (n=49) 66%; P=0.02, OR=3.4], as did those with two HLA-DR mismatches [0+1 mismatch (n=91) 87% versus 2 mismatches (n=91) 70%; P<0.05, OR=2.4]. INTERPRETATION: We show that graft loss in the first 6 months of transplant is significantly influenced by four HLA-A+-B mismatches. HLA-DR mismatch significantly increases the number of rejection episodes within the first year, without influencing graft survival. After 12 months both >4 rejection episodes in the first year and two HLA-DR mismatches are markers for late graft loss. We postulate that immunological graft loss in the first 6 months is dominated by the direct allorecognition pathway driven by HLA-DR mismatch. This mechanism is later lost or suppressed. Our data highlight HLA-DR mismatch as a marker for late graft loss and we show an advantage to avoiding transplanting hearts with six HLA-A+-B+-DR mismatches and to minimizing HLA-DR mismatches whenever possible.     

Tricuspid valve papillary fibroelastoma: a rare tumor with a diagnostic dilemma

Papillary fibroelastoma is a rare primary tumor of the heart valves. This lesion can occur on any of the valves or endothelial surface of the heart and has been detected by echocardiography, by cardiac catheterization, during open heart operations for other conditions, and at autopsy. Because of the potential for comorbidities, this tumor should be removed. We present the case of an elderly man with a diagnosis of severe mitral valve regurgitation and moderate tricuspid valve regurgitation who was suspected to have a tricuspid valve vegetation. Mitral valve replacement, tricuspid valve repair, and excision of the lesion were performed successfully. A histologic examination of the vegetation confirmed it to be a papillary fibroelastoma. We present this case to emphasize the rarity of this tumor and the importance of a correct diagnosis to avoid delaying its prompt and definitive management.     

Incidence of and Risk Factors for Screw Loosening after Iliosacral Screw Fixation for Posterior Pelvic Ring Injury

Purposes

Screw loosening is a common complication of iliosacral screw fixation, with subsequent loss of stability and fracture re-displacement. This study aimed to investigate the incidence of and risk factors for screw loosening after iliosacral screw fixation for posterior pelvic ring injury.

Methods

A total of 135 patients with posterior pelvic ring injuries who were treated with iliosacral screw fixation in our department between July 2015 and April 2021 were selected for this retrospective analysis. The possible risk factors for screw loosening were investigated using univariate and multivariate logistic regression analyses of patient demographics and trauma-related and iatrogenic variables, including age, sex, body mass index, Osteoporosis Self-Assessment Tool for Asians (OSTA) index, mechanism of injury, Young–Burgess classification, site of injury, type of injury, type of screw, mode of fixation, numbers of guidewire adjustments, accuracy of screw position, and quality of fracture reduction.

Results

The incidence of screw loosening was 15.6% (n = 21). The mean duration for screw loosening was 3.2 ± 1.5 months after operation. Univariate analysis results showed that the Young–Burgess classification, type of injury, site of injury, type of screw, mode of fixation, and OSTA index might be related to screw loosening (p < 0.05). According to the multivariate logistic regression, vertical shear injuries (Odds ratios [OR] 9.80, 95% Confidence intervals [CI] [1.96–73.28], p = 0.008), type of injury (OR 0.25, 95% CI [0.13–0.79], p = 0.027), common screws (OR 6.94, 95% CI [1.53–31.40], p = 0.012), screws insertion only at the level of the first sacral segment (S1) (OR 8.79, 95% CI [1.18–65.46], p = 0.034), injury site located in the medial sacral foramina (OR 6.28, 95% CI [1.16–34.06], p = 0.033), and lower OSTA index [OR 0.41, 95% CI [0.24–0.71], p = 0.001] were significantly related to screw loosening.

Conclusions

Vertical shear injuries, sacral fractures, injury site located in the medial sacral foramina, and lower OSTA index are significantly associated with the postoperative occurrence of screw loosening. Transiliac–transsacral screw fixation and screws insertion both at the level of the S1 and second sacral segment can prevent screw loosening.     

Open Arthrolysis for Chronic Elbow Dislocation with Extremely Severe Stiffness in Children

Objective

Studies on extremely severe elbow stiffness after chronic dislocation in children are scarce. This study aims to investigate the choice of surgical treatment modalities and to analyze their treatment efficacy in children with chronic elbow dislocation with extremely severe periarticular stiffness.

Methods

Data of 21 children with chronic elbow dislocation with extremely severe periarticular stiffness diagnosed and treated in our department between February 2015 and February 2021 were retrospectively analyzed. Twenty boys and one girl were included in the study, their mean age was 11 ± 2.5 years, and they had concomitant distal humerus fractures. For the treatment protocol, all children with extremely severe elbow stiffness were treated with open arthrolysis, and elbow joint stability was intraoperatively assessed. All children performed passive functional exercises the day after surgery. The elbow flexion and extension angles, range of motion (ROM), and Mayo score were evaluated preoperatively and at the final follow-up.

Results

Of the 21 children, only one had recurrent severe stiffness of the elbow joint after surgery; nevertheless, the function was still improved compared with that before surgery. Preoperatively, the mean elbow extension and flexion angles were 72.2° ± 12.7° and 93.6° ± 11.1°, respectively, and the range of motion (ROM) of the elbow joint was 17.8° ± 8.3°. At the final follow-up, the mean elbow extension and flexion angles were 22.7° ± 18.6° and 118.8° ± 15.4°, respectively, and the elbow joint ROM was 96.1° ± 17.4°. The differences in the preoperative and postoperative ROMs, flexion angles, and extension angles of the elbow joint were significant (p < 0.01). The MEPS at the final follow-up was 78.57 ± 14.24, which was significantly higher than preoperative (29.76 ± 10.89), and the excellent rate was 81%.

Conclusion

Open arthrolysis and open reduction and internal fixation of the elbow joint are effective in treating chronic elbow dislocation with extremely severe stiffness in children.