Pregnancy loss in major fetal congenital heart disease: incidence, risk factors and timing

OBJECTIVE

Fetuses with congenital heart disease (CHD) are at increased risk of pregnancy loss compared with the general population. We aimed to assess the incidence, timing and risk factors of pregnancy loss in cases with major fetal CHD, overall and according to cardiac diagnosis.

METHODS

This was a retrospective, population-level cohort study of fetuses and infants diagnosed with major CHD between 1997 and 2018 identified by the Utah Birth Defect Network (UBDN), excluding cases with termination of pregnancy and minor cardiovascular diagnoses (e.g. isolated aortic/pulmonary pathology and isolated septal defects). The incidence and timing of pregnancy loss were recorded, overall and according to CHD diagnosis, with further stratification based on presence of isolated CHD vs additional fetal diagnosis (genetic diagnosis and/or extracardiac malformation). Adjusted risk of pregnancy loss was calculated and risk factors were assessed using multivariable models for the overall cohort and prenatal diagnosis subgroup.

RESULTS

Of 9351 UBDN cases with a cardiovascular code, 3251 cases with major CHD were identified, resulting in a study cohort of 3120 following exclusion of cases with pregnancy termination (n = 131). There were 2956 (94.7%) live births and 164 (5.3%) cases of pregnancy loss, which occurred at a median gestational age of 27.3 weeks. Of study cases, 1848 (59.2%) had isolated CHD and 1272 (40.8%) had an additional fetal diagnosis, including 736 (57.9%) with a genetic diagnosis and 536 (42.1%) with an extracardiac malformation. The observed incidence of pregnancy loss was highest in the presence of mitral stenosis (< 13.5%), hypoplastic left heart syndrome (HLHS) (10.7%), double-outlet right ventricle with normally related great vessels or not otherwise specified (10.5%) and Ebstein's anomaly (9.9%). The adjusted risk of pregnancy loss was 5.3% (95% CI, 3.7-7.6%) in the overall CHD population and 1.4% (95% CI, 0.9-2.3%) in cases with isolated CHD (adjusted risk ratio, 9.0 (95% CI, 6.0-13.0) and 2.0 (95% CI, 1.0-6.0), respectively, based on the general population risk of 0.6%). On multivariable analysis, variables associated with pregnancy loss in the overall CHD population included female fetal sex (adjusted odds ratio (aOR), 1.6 (95% CI, 1.1-2.3)), Hispanic ethnicity (aOR, 1.6 (95% CI, 1.0-2.5)), hydrops (aOR, 6.7 (95% CI, 4.3-10.5)) and additional fetal diagnosis (aOR, 6.3 (95% CI, 4.1-10)). On multivariable analysis of the prenatal diagnosis subgroup, years of maternal education (aOR, 1.2 (95% CI, 1.0-1.4)), presence of an additional fetal diagnosis (aOR, 2.7 (95% CI, 1.4-5.6)), atrioventricular valve regurgitation ≥ moderate (aOR, 3.6 (95% CI, 1.3-8.8)) and ventricular dysfunction (aOR, 3.8 (95% CI, 1.2-11.1)) were associated with pregnancy loss. Diagnostic groups associated with pregnancy loss were HLHS and variants (aOR, 3.0 (95% CI, 1.7-5.3)), other single ventricles (aOR, 2.4 (95% CI, 1.1-4.9)) and other (aOR, 0.1 (95% CI, 0-0.97)). Time-to-pregnancy-loss analysis demonstrated a steeper survival curve for cases with an additional fetal diagnosis, indicating a higher rate of pregnancy loss compared to cases with isolated CHD (P < 0.0001).

CONCLUSIONS

The risk of pregnancy loss is higher in cases with major fetal CHD compared with the general population and varies according to CHD type and presence of additional fetal diagnoses. Improved understanding of the incidence, risk factors and timing of pregnancy loss in CHD cases should inform patient counseling, antenatal surveillance and delivery planning. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Stillbirth and fetal anomalies: secondary analysis of a case-control study

OBJECTIVE

Approximately 10% of stillbirths are attributed to fetal anomalies, but anomalies are also common in live births. We aimed to assess the relationship between anomalies, by system and stillbirth.

DESIGN

Secondary analysis of a prospective, case-control study.

SETTING

Multicentre, 59 hospitals in five regional catchment areas in the USA.

POPULATION OR SAMPLE

All stillbirths and representative live birth controls.

METHODS

Standardised postmortem examinations performed in stillbirths, medical record abstraction for stillbirths and live births.

MAIN OUTCOME MEASURES

Incidence of major anomalies, by type, compared between stillbirths and live births with univariable and multivariable analyses using weighted analysis to account for study design and differential consent.

RESULTS

Of 465 singleton stillbirths included, 23.4% had one or more major anomalies compared with 4.3% of 1871 live births. Having an anomaly increased the odds of stillbirth; an increasing number of anomalies was more highly associated with stillbirth. Regardless of organ system affected, the presence of an anomaly increased the odds of stillbirth. These relationships remained significant if stillbirths with known genetic abnormalities were excluded. After multivariable analyses, the adjusted odds ratio (aOR) of stillbirth for any anomaly was 4.33 (95% CI 2.80-6.70) and the systems most strongly associated with stillbirth were cystic hygroma (aOR 29.97, 95% CI 5.85-153.57), and thoracic (aOR16.18, 95% CI 4.30-60.94) and craniofacial (aOR 35.25, 95% CI 9.22-134.68) systems.

CONCLUSIONS

In pregnancies affected by anomalies, the odds of stillbirth are higher with increasing numbers of anomalies. Anomalies of nearly any organ system increased the odds of stillbirth even when adjusting for gestational age and maternal race.

TWEETABLE ABSTRACT

Stillbirth risk increases with anomalies of nearly any organ system and with number of anomalies seen.

The hemodynamic and adrenergic effects of perioperative dexmedetomidine infusion after vascular surgery

We tested dexmedetomidine, an alpha(2) agonist that decreases heart rate, blood pressure, and plasma norepinephrine concentration, for its ability to attenuate stress responses during emergence from anesthesia after major vascular operations. Patients scheduled for vascular surgery received either dexmedetomidine (n = 22) or placebo (n = 19) IV beginning 20 min before the induction of anesthesia and continuing until 48 h after the end of surgery. All patients received standardized anesthesia. Heart rate and arterial blood pressure were kept within predetermined limits by varying anesthetic level and using vasoactive medications. Heart rate, arterial blood pressure, and inhaled anesthetic concentration were monitored continuously; additional measurements included plasma and urine catecholamines. During emergence from anesthesia, heart rate was slower with dexmedetomidine (73 +/- 11 bpm) than placebo (83 +/- 20 bpm) (P = 0.006), and the percentage of time the heart rate was within the predetermined hemodynamic limits was more frequent with dexmedetomidine (P < 0.05). Plasma norepinephrine levels increased only in the placebo group and were significantly lower for the dexmedetomidine group during the immediate postoperative period (P = 0.0002). We conclude that dexmedetomidine attenuates increases in heart rate and plasma norepinephrine concentrations during emergence from anesthesia.

IMPLICATIONS

The alpha(2) agonist, dexmedetomidine, attenuates increases in heart rate and plasma norepinephrine concentrations during emergence from anesthesia in vascular surgery patients.

Intraoperative somatosensory evoked potential monitoring predicts peripheral nerve injury during cardiac surgery

BACKGROUND

Brachial plexus injury may occur without obvious cause in patients undergoing cardiac surgery. To determine whether such peripheral nerve injury can be predicted intraoperatively, we monitored somatosensory evoked potentials (SEPs) from bilateral median and ulnar nerves in 30 patients undergoing coronary artery bypass surgery.

METHODS

SEPs were analyzed for changes during central venous cannulation and during use of the Favoloro and Canadian self-retaining sternal retractors, events hereto implicated in brachial plexus injury. Brachial plexus injury was evaluated during physical examination in the postoperative period by an individual blinded to results of SEP monitoring.

RESULTS

Central venous cannulation was associated with transient changes in SEPs in four patients (13%). These changes occurred intermittently during insertion of the cannula but completely resolved within 5 min. Postoperative neurologic deficits did not occur in these cases. Use of the Canadian and Favoloro retractors was associated with significant changes in 21 patients (70%). In 16 of these, waveforms reverted toward baseline levels intraoperatively and were not associated with postoperative neurologic deficits. Five patients demonstrated a neurologic deficit postoperatively. In each of these, SEP change associated with use of surgical retractors persisted to the end of surgery compared to the immediate pre-bypass period.

CONCLUSION

Intraoperative upper extremity SEPs may be used to predict peripheral nerve injury occurring during cardiac surgery.

A new surgical monitoring and resuscitation cart

To enhance patient safety after cardiac surgery, a new surgical cart has been designed to allow monitoring and resuscitation during transport of patients from operating room to intensive care unit.

A comparison of the neuromuscular blocking and vagolytic effects of ORG NC45 and pancuronium

ORG NC45, a neuromuscular blocking agent not producing tachycardia, was examined first, to establish the kinetics of the anatagonism it produces, and second, to test the hypothesis that the tachycardia seen with pancuronium and gallamine reflects an action on vagal postganglionic nerve endings. The action of ORG NC45 was studied on end-plate depolarization and neuromuscular transmission in the guinea pig lumbrical muscle. Also, the effect of ORG NC45 on the response of the cardiac pacemaker to carbachol and on the response of the pacemaker to pre- and postganglionic vagal stimulation was examined in isolated guinea pig atria. ORG NC45 was a potent neuromuscular blocking agent (twice as potent as pancuronium) in this species and showed typical competitive kinetics with a dissociation constant of 0.0103 micro M. However, ORG NC45 affected the atrial system only at very high concentrations and did not affect release of transmitter from vagal nerve terminals. These results thus confirm the hypothesis that presence or absence of vagolytic action goes hand-in-hand with tachycardia or its absence clinically.

Effects of non-depolarizing neuromuscular blocking agents on the cardiac vagus nerve in the guineapig

The ability of gallamine, metocurine, pancuronium, tubocurarine and atropine to block the response to postganglionic stimulation of the vagus nerve were measured in isolated, spontaneously beating guineapig atria. From analysis of the results in conjunction with those of earlier assays of concentrations that block effects of preganglionic vagal stimulation, it was concluded that only tubocurarine possessed ganglionic blocking activity. From calculation of the extent of block of muscarinic receptors at drug concentrations which blocked the response to postganglionic vagal stimulation, it was concluded that gallamine and pancuronium have an antivagal action exerted most probably on the postganglionic nerve terminal, and that this action is the most likely explanation of the tachycardia seen clinically with these two drugs.

A vagolytic action of neuromuscular blocking agents at the pacemaker of the isolated guinea pig atrium

To examine the basis of tachycardia seen clinically with some neuromuscular blocking agents, the potencies of d-tubocurarine, dimethyltubocurarine, gallamine, and pancuronium in antagonizing the effects of vagal stimulation on the guinea pig atrial pacemaker were determined and expressed as an ED50 for vagal blockade. These ED50 values were compared with the respective potency values of these agents at the motor endplate. This comparison showed that in clinical doses, gallamine and pancuronium may reach levels that produce vagal blockade. Comparison with atropine indicated that the vagolytic action of the neuromuscular blocking agents was not attributable to receptor occlusion, but reflected instead an action on the vagus nerve itself.

Potencies of neuromuscular blocking agents at the receptors of the atrial pacemaker and the motor endplate of the guinea pig

Drug receptor dissociation constants (KB) were determined for four neuromuscular relaxants at the cardiac pacemaker as well as at the motor endplate. The ratios KB(atrium)/KB(lumbrical) were found to be high for d-tubocurarine and dimethyltubocurarine, 264 and 136, respectively. Thus, interaction at muscarinic sites would occur only with large doses of these drugs. In contrast, the ratios were low for pancuronium and gallamine, 5.3 and 2.4, respectively. Hence, the concentrations of these drugs needed for clinical neuromuscular blockade would occupy appreciable fractions of cardiac muscarinic receptors, and thus might produce vagal blockade and thereby produce the tachycardia seen clinically with these two agents.