Effect of ligation of patent ductus arteriosus on left ventricular performance and its determinants in premature neonates

Hemodynamic evaluation of extremely low birth weight infants during the first 7 days of life

BACKGROUND AND AIM

We aimed to investigate the hemodynamic status of extremely low birth weight (ELBW) infants during the transitional period under intensive management.

METHODS

This retrospective cohort study analyzed left ventricular ejection fraction (LVEF), left ventricular end-systolic wall stress (ESWS), left ventricular internal dimension in diastole (LVIDd), and mean arterial pressure (MAP) of ELBW infants during their first week of life. Small for gestational age (SGA), histological chorioamnionitis (hCAM), severe intraventricular hemorrhage (IVH), and non-survival to discharge infants were compared to their counterparts.

RESULTS

Sixty-two infants (25.7 ± 2.1 weeks, 700.7 ± 165.4 g) were analyzed. MAP gradually increased. Median LVEF was 69.8 % on day 1, decreased to 62.7 % on day 2, then increased throughout the week. ESWS was lowest at birth, rose to 28.2 g/cm2 on day 2, and decreased on day 6. There were no significant changes in LVIDd. SGA infants had higher MAP throughout, higher LVEF on day 2 and 3, but lower LVEF on day 5 to 7. LVIDd was lower in hCAM group. Severe IVH group had a more significant drop in LVEF on day 2, higher ESWS, and a higher incidence of hemodynamic significant patent ductus arteriosus (hsPDA). Non-survival had lower LVIDd.

CONCLUSIONS

MAP increased gradually. Hemodynamic instability was observed in the first two days, with decreased LVEF and increased ESWS before stabilization. We observed an alteration in hemodynamic adaptation in SGA and hCAM infants. Severe IVH group experienced early hemodynamic instability and a higher incidence of hsPDA.

A Retrospective Cohort Evaluation of Left Ventricular Remodeling, Perioperative Complications and Outcome in Medium and Large Size Dogs with Patent Ductus Arteriosus after Percutaneous Closure

This retrospective cohort study included one hundred fifty-seven medium and large-size dogs with the aim of evaluating the effect of signalment and echocardiographic features on complications, outcomes and left ventricular modifications before and after patent ductus arteriosus (PDA) closure. The patients were divided in two groups based on the heart remodeling after closure: Group A included dogs that had a reduction in the end-systolic volume index (ESVI) after closure compared to the ESVI measured before; Group B included dogs without a reduction in ESVI after closure. Body weight, minimal ductal diameter (MDD) of PDA, end-diastolic volume index and presence of arrhythmias at presentation were significantly higher in Group B compared to Group A. The shortening fraction and ejection fraction after closure were reduced in both groups, but in Group B there was a major reduction, and the mean values indicated a possible systolic dysfunction. Complications during the procedure and death due to cardiac reasons were greater in Group B compared to Group A. In conclusion, a higher body weight, a larger MDD, a more severe heart enlargement or arrhythmias at presentation increased the risk of developing a worsening structural and functional condition after ductal closure, and this can be associated with perioperative complications and cardiac death.

Percutaneous Closure of Patent Ductus Arteriosus

Percutaneous-based patent ductus arteriosus closure is technically feasible among infants less than 1.5 kg. However, marked heterogeneity in the type and nature of adverse events obscures current safety profile assessments. Although data on the risks of postdevice closure syndrome remain promising, a lack of comparative trials of surgical ductal ligation and inconsistent surveillance across published studies obscure confidence in present estimates of safety and efficacy. To minimize risk and yield the greatest benefits, clinical studies of patent ductus arteriosus treatment should consider incorporating more robust assessments to ensure that infants at greatest risk for adverse ductal consequences are included.

Which Inotropic Drug, Dobutamine or Milrinone, Is Clinically More Effective in the Treatment of Postligation Cardiac Syndrome in Preterm Infants?

OBJECTIVE

This study aimed to detect which of the two main medicines suggested in the treatment of postligation cardiac syndrome (PLCS)-dobutamine or mirinone-possesses a more therapeutic effect. While doing this, clinicians are provided with a broader perspective on the treatment and follow-up of cases. The desire was to increase the treatability and monitor ability of the cases in question and hence their survivability.

STUDY DESIGN

A retrospective review of a cohort of infants with PLCS was conducted between March 2012 and December 2018. In the treatment of infants with PLCS, dobutamine (dobutamine study group-DSG) or milrinone (milrinone study group-MSG) was used. The respiration, cardiac, echocardiography, and perfusion parameters of the cases were assessed both before and after ligation. Based on the data obtained, both the effects of the medicines on PLCS and the difference between their therapeutic effects were studied. The accuracy of prognostication was assessed with receiver operating characteristic analyses.

RESULTS

PLCS was detected in 29 (34.1%) of 85 patent ductus arteriosus ligation cases in total. Of all the PLCS cases, 13 (44.8%) were treated with dobutamine and 16 (55.2%) with milrinone. It was observed that the effects of the medicines on the respiratory system and cardiovascular system manifested in the third and 6th hour, respectively. It was detected that both medicines had more effect on the systolic blood pressure (SBP) (area under the curve [AUC]: 0.997/0.996, p = 0.001/0.002) than on the diastolic blood pressure (AUC: 0.911/0.843, p = 0.032/0.046).

CONCLUSION

Dobutamine and milrinone, two primary medicines that can be used in the treatment of cases with PLCS, possess similar therapeutic effects on this pathology. In addition, their postoperative therapeutic effects on the SBP are more in the foreground.

Management of Patent Ductus Arteriosus in Premature Infants in 2020

The patent ductus arteriosus (PDA) is the most commonly found cardiac condition in neonates. While there have been several studies and thousands of publications on the topic, the decision to treat the PDA is still strongly debated among cardiologists, surgeons, and neonatologists. This is in part due to the shortage of long-term benefits with the interventions studied. Practice variations still exist within sub-specialties and centers. This article briefly summarizes the history, embryology and histology of the PDA. It also succinctly discusses the hemodynamic significance of a PDA which builds the framework to review all the available literature on PDA closure in premature infants, though not a paradigm shift just yet; it introduces transcatheter PDA closure (TCPC) as a possible armament to the clinician for this age-old problem.

Prediction value of pulmonary hypertension in newly identified left ventricular dysfunction among adult patients after patent ductus arteriosus closure

The present study aimed to propose the pulmonary hypertension for predicting left ventricular dysfunction in adults after patent ductus arteriosus closure. A total of 183 patients (age ≥18 years) after patent ductus arteriosus occlusion were retrospectively collected in this study. In brief, pre-, post-procedure and short-term follow-up transthoracic echocardiography were performed. Simpson’s method was used to measure the left ventricular ejection fraction (LVEF), and LVEF less than 50% after procedure was utilized as a criterion to identify left ventricular dysfunction. As a result, 36 (19.67%) patients developed newly identified left ventricular dysfunction. The rate of newly identified left ventricular dysfunction was significantly higher in moderate or severe pulmonary hypertension groups compared to the groups of mean pulmonary artery pressure (mPAP) <25 mmHg (P < .001). Logistic regression analysis showed that elevated mPAP ( ≥25 mmHg) was an independent predictive value for newly identified left ventricular dysfunction (OR = 3.584, 95%CI: 1.186–10.832, P = .024) after adjusting confounders. The ROC curve revealed a good discrimination power for predicting newly identified left ventricular dysfunction (AUC = 0.924, 95%CI: 0.885–0.963, P < .001). Taken together, newly identified left ventricular dysfunction after patent ductus arteriosus closure was prevalent in patients with elevated mPAP. The pre-procedure elevated mPAP is an independent risk factor for the prediction of the newly identified left ventricular dysfunction in adult patients undergoing percutaneous patent ductus arteriosus closure. It is feasible to propose a risk model for predicting post-procedure left ventricular dysfunction and a heart function monitoring in pulmonary hypertension patients.

Acute ascending aortic dissection due to transcatheter patent ductus arteriosus closure in the elderly: An extremely rare complication of transcatheter patent ductus arteriosus closure

It is well known that patent ductus arteriosus (PDA) in adults, especially in the elderly, differs from that in pediatric patients. A 68-year-old woman with a PDA with focal calcification at the aortic orifice of the ampulla with a minimum diameter of 4.0 mm and length of 14.8 mm, was treated with a 10/8-mm Amplatzer duct occluder (ADO) (St. Jude Medical Corp, St. Paul, MN, USA). After device implantation, systolic blood pressure (BP) increased to approximately 220 mmHg from 130 mmHg. She experienced transient dyspnea from hypertensive heart failure, which improved through continuous infusion of anti-hypertensive agents. She suddenly felt pressure on her chest 12 h post-procedure and collapsed. Surgical thoracotomy revealed an ascending aortic dissection into the pericardial space. In retrospective review, the ADO may have been slightly deformed by fluoroscopy. The complication may have been triggered by the resilience caused by device deformation, damage to the aortic wall due to the aortic side of the device, uneven elasticity of the arterial wall, and uncontrolled excessively high blood pressure. <Learning objective: Although transcatheter patent ductus arteriosus (PDA) closure is an established, safe, and effective procedure when treating PDA of the elderly, wall damage due to the device may occur because of atherosclerotic changes different from that of younger patients and blood pressure will rise after closure. Therefore, it is necessary to carefully select the type and size of the device and to strictly control blood pressure in patients with a history of hypertension.>.

Post-Patent Ductus Arteriosus ligation syndrome with hypertension and masking of renal artery stenosis in an infant

Post-patent ductus arteriosus ligation syndrome is common, but rarely has hypertension been described following ductal ligation with an unclear mechanism. We report a case of an infant who exhibited features of post-patent ductus arteriosus ligation syndrome and hypertension, but was found to have bilateral renal artery stenosis. Increased systemic vascular resistance can be masked by the parallel circuit physiology of a patent ductus arteriosus.

Preoperative echocardiographic measures of left ventricular mechanics are associated with postoperative vasoactive support in preterm infants undergoing patent ductus arteriosus ligation

OBJECTIVE

Preoperative risk factors associated with poor outcomes after patent ductus arteriosus ligation in preterm infants have not been well defined. The aim of this study was to determine the association between preoperative echocardiographic measures of left ventricular mechanics and postoperative clinical outcomes after patent ductus arteriosus ligation.

METHODS

Preterm infants less than 90 days of age with no other significant congenital anomalies who underwent patent ductus arteriosus ligation between 2007 and 2015 were considered for retrospective analysis. The primary outcome was peak postoperative vasoactive inotropic score. Conventional echocardiographic measures of ventricular size, function, and patent ductus arteriosus size were performed. Echocardiographic single-beat, pressure-volume loop analysis estimates of contractility (end-systolic elastance) and afterload (arterial elastance) were calculated. Ventriculoarterial coupling was assessed using the arterial elastance/end-systolic elastance ratio. Multivariable linear regression was performed using clinical and echocardiographic data.

RESULTS

Echocardiograms from 101 patients (42.5% male) were analyzed. We found a statistically significant association between vasoactive inotropic score and both end-systolic elastance and arterial elastance. No patient with arterial elastance/end-systolic elastance greater than 0.78 (n = 32) had a vasoactive inotropic score 20 or greater. Analysis of our secondary outcomes found associations between preoperative end-systolic elastance and postoperative urine output less than 1 mL/kg/h at 24 hours, creatinine change greater than 0.5 mg/dL, and time to first extubation.

CONCLUSIONS

End-systolic elastance and arterial elastance were the only predictors of postoperative vasoactive inotropic score after patent ductus arteriosus ligation in preterm infants. Those neonates with increased contractility and low afterload were at highest risk for elevated inotropic support. These findings suggest a role for echocardiographic end-systolic elastance and arterial elastance in the preoperative assessment of preterm infants undergoing patent ductus arteriosus ligation.

Circulatory Management Focusing on Preventing Intraventricular Hemorrhage and Pulmonary Hemorrhage in Preterm Infants

The goal of modern neonatal care of extremely preterm infants is to reduce mortality and long-term neurological impairments. Preterm infants frequently experience cerebral intraventricular or pulmonary hemorrhage, which usually occurs within 72 hours after birth and can lead to long-term neurological sequelae and mortality. These serious hemorrhagic complications are closely related to perinatal hemodynamic changes, including an increase in the afterload on the left ventricle of the heart after the infant is separated from the placenta, and an increased preload from a left-to-right shunt caused by a hemodynamically significant patent ductus arteriosus (PDA). The left ventricle of a preterm myocardium has limited ability to respond to such an increase in afterload and preload, and this can result in cardiac dysfunction and hemodynamic deterioration. We suggest that delayed umbilical cord clamping or umbilical cord milking to maintain optimal blood pressure and systemic blood flow (SBF), careful assessment to keep the afterload at an acceptable level, and a strategy of early targeted treatment of significant PDA to improve perfusion during this critical time period may reduce or prevent these serious complications in preterm infants.

Left Ventricular Dysfunction after Closure of Large Patent Ductus Arteriosus

Changes in left ventricular dimensions and performance were studied in 43 patients after transcatheter occlusion or surgical ligation of patent ductus arteriosus. The patients were assigned to 2 groups based on their ductal diameter: ≥ 3.1 mm to group A ( n = 27) and ≤ 3 mm to group B ( n = 16). The mean age and weight of the groups were comparable. Before intervention, group A had a significantly larger mean left ventricular end-diastolic diameter than group B, while all patients had normal shortening fraction and ejection fraction. Within 1 month after intervention, left ventricular end-diastolic diameter showed a trend towards regression while shortening fraction and ejection fraction decreased significantly in group A. There were no significant changes in these parameters in group B. Between 1 and 6 months after intervention, left ventricular performance improved in most of the group A patients who were followed up. We conclude that closure of large ductus arteriosus in children leads to significant immediate deterioration of left ventricular performance, which appears to recover within a few months. Echocardiographic study before hospital discharge is recommended in these patients. Serious deterioration of ventricular performance after closure may warrant the use of angiotensin converting enzyme inhibitors.

Hemodynamic alterations recorded by electrical cardiometry during ligation of ductus arteriosus in preterm infants

This is a prospective study using non-invasive electrical cardiometry to measure hemodynamic changes during surgical ligation of patent ductus arteriosus (PDA) in very low birth weight (VLBW, ≤1500 g) infants. The aims of this study were to examine hemodynamic aberration caused by abrupt closure of a ductal shunting and to define factors that affect hemodynamic changes. Simultaneous measurements of heart rate (HR), stroke volume (SV), cardiac output (CO), and systemic vascular resistance (SVR) were collected at ten time points: 1 h prior to anesthesia, at the beginning of anesthesia, starting of surgery, immediately after PDA being ligated, and 1 h followed by 6, 12, 18, 24, and 48 h after the surgery. Thirty infants with gestational age of 27.7 ± 2.0 weeks and birth weight of 929 ± 280 g were studied. Upon sudden termination of ductal shunting, there was a significant decline in CO to 73 % of presurgery baseline. The deterioration in CO was associated with a decreased SV rather than HR. At the same time, there was an increase of SVR following ductal ligation. Magnitude of CO and SV reduction were higher in smaller infants (≤1 kg), and recovery was to a lesser degree in infants with more severe PDA.

CONCLUSION

Reduced stroke volume and elevated vascular resistance contribute to the major hemodynamic aberrations in VLBW infants receiving PDA ligation surgery.

Catecholamine-resistant hypotension and myocardial performance following patent ductus arteriosus ligation

OBJECTIVE

We performed a multicenter study of preterm infants, who were about to undergo patent ductus arteriosus ligation, to determine whether echocardiographic indices of impaired myocardial performance were associated with subsequent development of catecholamine-resistant hypotension following ligation.

STUDY DESIGN

A standardized treatment approach for hypotension was followed at each center. Infants were considered to have catecholamine-resistant hypotension if their dopamine infusion was > 15 μg kg(-1)min(-1). Echocardiograms and cortisol measurements were obtained between 6 and 14 h after the ligation (prior to the presence of catecholamine-resistant hypotension).

RESULT

Forty-five infants were enrolled, 10 received catecholamines (6 were catecholamine-responsive and 4 developed catecholamine-resistant hypotension). Catecholamine-resistant hypotension was not associated with decreased preload, shortening fraction or ventricular output. Infants with catecholamine-resistant hypotension had significantly lower levels of systemic vascular resistance and postoperative cortisol concentration.

CONCLUSION

We speculate that low cortisol levels and impaired vascular tone may have a more important role than impaired cardiac performance in post-ligation catecholamine-resistant hypotension.

Assessment and treatment of post patent ductus arteriosus ligation syndrome

OBJECTIVE

To compare differences in tissue Doppler imaging, global longitudinal strain (GLS), and cardiac troponin T (cTnT) between infants with low (<200 mL/kg/min) and high (>200 mL/kg/min) left ventricular (LV) output 1 hour after duct ligation and assess the impact of milrinone treatment on cardiac output and myocardial performance.

STUDY DESIGN

LV function was assessed preoperatively and 1 and 18 hours postoperatively. Infants were categorized into a low-output or a normal-output group based on the echocardiographic assessment of LV output at 1 hour.

RESULTS

Thirty infants with a mean gestation of 25.3 weeks were enrolled. LV basal lateral S', basal septal S', and basal right ventricular S' were lower in the low-output group (n = 19) at 1 hour postoperatively, with no significant difference in GLS (low-output -10.3% vs high-output -14.4%, P >.05) or cTnT between the groups. Patients in the low-output group were treated with milrinone, and by 18 hours LV performance recovered to levels comparable with the high output group. cTnT values increased at 18 hours in the whole cohort with no significant difference between the groups.

CONCLUSION

Tissue Doppler imaging and GLS provide novel insights and further characterization of myocardial performance immediately after patent ductus arteriosus ligation. A reduction in tissue Doppler-derived LV systolic velocity may further help in monitoring cardiac performance after patent ductus arteriosus ligation and for monitoring the effects of treatment.

Preoperative left ventricular internal dimension in end-diastole as earlier identification of early patent ductus arteriosus operation and postoperative intensive care in very low birth weight infants

Patent ductus arteriosus (PDA) is common in premature infants. In very low birth weight infants (VLBWI), PDA requires surgical therapy in many cases. It is unclear to know at-risk infants showing cardio-dysfunction after PDA surgery. The purpose of this study was to identify at-risk infants showing cardio-dysfunction after surgery for patent ductus arteriosus (PDA). We examined the relationship between left ventricular (LV) performance before and after PDA ligation in a retrospective observational cohort study. We studied 64 preterm neonates with symptomatic PDA before and after surgical ligation. Echocardiographic examinations were performed pre- and postoperatively. M-mode measurements included left ventricular internal dimension in end-diastole (LVIDd) and LV fractional shortening (FS). All cases showed decreased LVFS after PDA closure. Most cases (49/64, 77%) showed postoperative FS decreased to below normal (<28%). Preoperative relative LVIDd was significantly larger in abnormal FS infants (137 ± 18%) than in normal FS infants (118 ± 11%; p<0.01). A cut-off value of preoperative relative LVIDd (absolute LVIDd/normal value) for predicting postoperative cardio-dysfunction was 127.4% (sensitivity, 0.735; specificity, 0.933; area under curve, 0.817). Determination of preoperative LVIDd might facilitate earlier identification of infants needing early PDA surgery and postoperative intensive care.

Left ventricular efficiency after ligation of patent ductus arteriosus for premature infants

OBJECTIVE

The purpose of this study was to evaluate the hemodynamic changes in left ventricular function before and after patent ductus arteriosus ligation in premature infants with regard to the energetic efficiency of left ventricular pumping.

METHODS

Thirty-five premature infants who underwent patent ductus arteriosus ligation were enrolled in this study. Left ventricular efficiency was evaluated at 4 points: within 24 hours before patent ductus arteriosus ligation, within 24 hours after patent ductus arteriosus ligation, between postoperative days 2 and 4, and on postoperative day 7. The indices of contractility (end-systolic elastance) and afterload (effective arterial elastance) were approximated on the basis of the systemic blood pressure and systolic or diastolic left ventricular volume. The ratio of stroke work and pressure-volume area, representing the ventricular efficiency, was estimated using the following theoretic formula: the ratio of stroke work and pressure-volume area = 1/(1 + 0.5 ventriculoarterial coupling).

RESULTS

Left ventricular efficiency was transiently deteriorated within 24 hours after patent ductus arteriosus ligation because of the marked increase of the afterload and the slight increase of contraction, and then recovered to preoperation levels by 2 to 4 days after patent ductus arteriosus ligation.

CONCLUSIONS

Analysis of indices representing the afterload, contractility, and energetic efficiency of the left ventricle may provide practical information for the management of premature infants during the postoperative period after patent ductus arteriosus ligation.

Pros and cons of patent ductus arteriosus ligation: hemodynamic changes and other morbidities after patent ductus arteriosus ligation

Although surgical ligation of a persistent patent ductus arteriosus resolves the adverse hemodynamic consequences of the systemic-to-pulmonary shunt and may confer some long-term benefits, it is also associated with both immediate and long-term negative effects. The population that benefits from or is harmed by the procedure is not clearly defined. Although indiscriminate ligation of the patent ductus arteriosus in all patients is not supported by the available information, the recent suggestion declaring the ductus harmless is not supported either. As we await the results of appropriately designed randomized control studies to define the indications for ligation, we must use clinical and echocardiographic indicators of a hemodynamically significant ductus arteriosus and thoughtful assessment of each individual patient to help guide us in addressing this complex problem.

Use of targeted neonatal echocardiography to prevent postoperative cardiorespiratory instability after patent ductus arteriosus ligation

OBJECTIVES

To investigate the value of targeted neonatal echocardiography (TnECHO) in predicting cardiorespiratory instability after patent ductus arteriosus (PDA) ligation, and to evaluate the impact of TnECHO-directed care.

STUDY DESIGN

We reviewed serial echocardiography evaluations of 62 preterm infants after PDA ligation to investigate the relationship between indices of myocardial performance and postoperative cardiorespiratory instability. A predictive model was developed based on TnECHO criteria, with targeted initiation of intravenous milrinone. A comparative evaluation was performed between matched infants in the previous era (epoch 1; n=25) and current era (epoch 2; n=27) of TnECHO-guided treatment.

RESULTS

Left ventricular output <200 mL/kg/min at 1 hour after PDA ligation was a sensitive predictor of systemic hypotension and the need for inotropes, and was used for initiation of i.v. milrinone infusion in epoch 2. Infants treated with milrinone had a lower incidence of ventilation failure (15% vs 48%; P=.02) and less need for inotropes (19% vs 56%; P=.01), and showed a trend toward improved oxygenation (P=.08).

CONCLUSION

TnECHO facilitates early detection of infants at greatest risk for subsequent cardiorespiratory deterioration. Administration of milrinone to neonates with low cardiac output may lead to improved postoperative stability.

Patent ductus arteriosus ligation is associated with impaired left ventricular systolic performance in premature infants weighing less than 1000 g

OBJECTIVE

Patent ductus arteriosus ligation is often complicated by systemic hypotension and oxygenation failure. The ability of the immature myocardium to compensate for altered afterload is poorly understood. The aim of this study was to characterize the effects of patent ductus arteriosus ligation on myocardial performance in preterm infants.

METHODS

Serial echocardiographic analysis was performed before and after patent ductus arteriosus ligation. Characteristics of the patent ductus arteriosus, myocardial performance (fractional shortening, mean velocity of circumferential fiber shortening, and left ventricular output) and left ventricular afterload (end-systolic wall stress) were assessed. The stress-velocity relationship was measured as a preload-independent, afterload-adjusted measure of myocardial contractility.

RESULTS

Forty-six preterm infants were assessed at 28.5 +/- 11.3 days and a weight of 1058 +/- 272 g. Patent ductus arteriosus ligation was followed by increased left ventricular exposed vascular resistance temporally coinciding with reduced left ventricular preload, decreased left ventricular contractility, and low left ventricular output. Neonates weighing 1000 g or less had a higher rate of low fractional shortening (<25%) or low left ventricular output (<170 mL x kg(-1) x h(-1)) and increased need for cardiotropes and demonstrated a trend toward an impaired stress-velocity relationship. Neonates with impaired left ventricular systolic performance were more likely to require cardiotropes and have low systolic arterial pressure, increased heart rate, and abnormal base deficit.

CONCLUSION

Patent ductus arteriosus ligation is sometimes associated with impaired left ventricular systolic performance, which is most likely attributable to altered loading conditions. Neonates weighing 1000 g or less are at increased risk of impaired left ventricular systolic performance, which might relate to maturational differences and decreased tolerance to altered loading conditions.

Cerebral and splanchnic hemodynamics after duct ligation in very low birth weight infants

OBJECTIVE

To describe mesenteric and cerebral blood flow velocities after surgical patent ductus arteriosus (PDA) closure in premature infants.

STUDY DESIGN

We measured middle cerebral artery (MCA), celiac artery (CA), and superior mesenteric artery (SMA) Doppler ultrasound scanning blood flow velocity (BFV) preoperatively, 3 and 24 hours after ligation.

RESULTS

We studied 32 infants, with a mean (+/- SD) birthweight of 762 +/- 170 g and gestational age of 25.6 +/- 1.4 weeks at a mean age of 34 +/- 13 days. Significant changes in end-diastolic (EDV), average velocity (AV), and vascular resistance were measured in all 3 vessels by 3 hours. AV increased significantly in the CA and SMA within 3 hours; however, no significant increase in MCA AV was found until 24 hours after surgery.

CONCLUSION

PDA ligation significantly changes BFV in the MCA, CA, and SMA. In the MCA vascular tone is acutely modulated, with no change in AV at 3 hours. In the CA and SMA, AV increases acutely after ligation. These different patterns of change in BFV suggest region-specific adaptation to surgical PDA closure.

Acute hemodynamic decompensation following patent ductus arteriosus ligation in premature infants

INTRODUCTION

Patent ductus arteriosus (PDA) ligation can lead to postoperative hemodynamic instability requiring inotropic support, termed hemodynamic decompensation. The purpose of this study was to prospectively determine the incidence, predictors, and clinical impact of hemodynamic decompensation after PDA ligation in preterm infants.

METHODS

All infants undergoing PDA ligation were eligible for this prospective cohort study. After undergoing ligation, patients were followed until 30 days after successful extubation, discharge from the NICU, or death. Data collection included perinatal and preoperative clinical information, operative details, postoperative course, and outcome.

RESULTS

Ninety-six preterm infants were enrolled and underwent PDA ligation. Hemodynamic decompensation occurred in 27 patients (28%). Overall in-hospital mortality rate was 18%. Mortality was significantly higher among infants that developed hemodynamic decompensation (33% vs 11%, p = .012). Hemodynamic decompensation was associated with an adjusted odds ratio (OR) for death of 3.1 (95% confidence interval: 1.0-9.5, p = .05). Lower estimated gestational age, lower corrected age, and higher rate of preoperative mechanical ventilation were significant predictors of hemodynamic decompensation.

CONCLUSION

Hemodynamic decompensation occurred in 28% of patients after PDA ligation, resulting in a significantly higher mortality. Younger patients requiring higher ventilator support are most likely to develop hemodynamic decompensation.

Changes in myocardial function and hemodynamics after ligation of the ductus arteriosus in preterm infants

OBJECTIVE

To characterize the changes in systemic hemodynamics and systolic, diastolic, and global myocardial performance after patent ductus arteriosus (PDA) ligation in very-low-birth-weight infants.

STUDY DESIGN

Echocardiograms were performed on 23 neonates (mean gestational age, 26.2 +/- 2.2 weeks) at 2.3 +/- 2.0 hours before PDA ligation (n = 23) and at 2.0 +/- 1.4 hours (n = 23) and 23.5 +/- 2.5 hours after (n = 11) PDA ligation.

RESULTS

Mean blood pressure, heart rate, load-independent contractility, shortening fraction, left ventricular (LV) afterload, and diastolic function did not change. Preload (early and atrial mitral inflow velocities) decreased immediately after ligation but remained unchanged thereafter. LV output decreased and systemic vascular resistance increased after surgery. The LV myocardial performance index (MPI), a measure of global myocardial performance, deteriorated acutely after ligation but improved by 23.5 hours after surgery. Changes in LV MPI were most closely correlated with changes in LV output.

CONCLUSIONS

After PDA ligation, LV output and MPI decrease, due primarily to a decrease in LV preload, although LV contractility and diastolic function do not change. However, the changes in LV MPI after ligation also reflect an acute deterioration followed by an improvement in global cardiac function, because LV loading conditions remained unchanged after surgery and thus cannot explain the improvement in MPI by 24 hours after ligation.

Myocardial contractility in premature neonates with and without patent ductus arteriosus

Controversy exists as to whether a hemodynamically significant left-to-right shunt due to a patent ductus arteriosus (PDA) affects ventricular contractility. Load-dependent indices such as ejection fraction and shortening fraction have traditionally been used to assess contractility, but the relationship between the rate-corrected velocity of fiber shortening (MVCFc) and wall stress may be more suitable, as it is a preload-independent, afterload-adjusted method of assessing ventricular contractility. Age-related differences have been established for these variables in normal adults and children and it has been recommended for use in the premature neonate. The study was performed to assess left ventricular contractility in premature neonates with a significant left-to-right shunt due to a PDA. Using echocardiography, we measured the relationship of MVCFc to stress at peak systole (SPS) in two groups of premature infants. Group 1 consisted of 15 controls (680-1495 g, 25-32 weeks' gestation), and Group 2 of 15 neonates with hemodynamically significant PDA (840-1635 g, 26-33 weeks' gestation). In both groups, MVCFc was linearly and inversely related to SPS ( p < 0.001). The regression equations were as follows: Group 1, MVCFc = -0.0153SPS + 1.70 ( R(2) = 0.68); and Group 2, MVCF = - 0.019SPS + 1.89 ( R(2) = 0.76). There was no significant difference in the relationship between the two groups, but their slopes were significantly steeper and had a higher Y-intercept than the relationship we previously reported for older children. This preliminary study establishes the normal MVCFc/SPS relationship in the premature neonate (25-33 weeks' gestation) and suggests that premature infants function at a higher resting contractile state than older children. A hemodynamically significant PDA has no effect on contractility. These data will be useful in assessing left ventricular contractility in premature neonates with other types of ventricular loading and noncardiac stress.

Transcatheter closure of a very large patent ductus arteriosus in a pregnant woman at 22 weeks of gestation

Successful transcatheter closure of a large PDA in a pregnant patient is reported using the Amplatzer ductal occluder device. This procedure was safe and uncomplicated, obviating the need for surgery in this high risk patient.

Serial echocardiographic and Doppler evaluation of left ventricular systolic performance and diastolic filling in premature infants

To examine the effects of somatic growth on left ventricular systolic and diastolic functions in premature infants, we performed serial two-dimensional, M-mode and Doppler echocardiograms of 18 premature infants in the early neonatal period (mean of 14 days) and on the day when they were discharged from the hospital (mean of 94 days). The relation between rate-corrected mean velocity of fiber shortening and end-systolic wall stress relation was used as a load-independent estimate of contractility. Diastolic function was assessed by transmitral Doppler filling velocity patterns. The end-systolic wall stress was significantly lower in the first examination than in the second examination (38+/-8 vs. 46+/-10 g/cm2, P < 0.005). However, there was no significant difference in the rate-corrected velocity of fiber shortening between the two examinations. An inverse linear relation between the end-systolic wall stress and the rate-corrected mean velocity of fiber shortening was found in each examination. The slopes of these two regression lines showed no significant difference, suggesting that the left ventricular contractility is on the same level during this study period. The transmitral Doppler flow velocity patterns markedly altered between the two observations. The peak E wave, peak A wave, peak E/A ratio, flow velocity time integral of E/A wave, the first third filling fraction, and the normalized peak filling rate to stroke volume increased significantly during the study period (78+/-14 vs. 31+/-9 cm/s, 61+/-12 vs. 33+/-7 cm/s, 1.29+/-0.18 vs. 0.93+/-0.19, 1.75+/-0.58 vs. 1.17+/-0.24, 0.42+/-0.07 vs. 0.37+/-0.05, and 9.48+/-1.71 vs. 7.30+/-0.96/s, respectively, P < 0.001), suggesting a relative shift of Doppler filling into the early diastole. We demonstrated that the age- and growth-related alterations in the transmitral Doppler filling patterns occurred dramatically without changes in contractility during the first 3 months after birth. This diastolic filling change may be related to the age-related maturation in the left ventricular diastolic properties.

Maturational changes in left ventricular contractile state

It has been suggested from animal and human studies that age-related alterations in left ventricular contractility occur. However, there is little information about growth-related changes in left ventricular performance from preterm infants to older children. In 22 preterm infants, 23 fullterm infants, and 35 children, left ventricular contractility was evaluated by two-dimensional and M-mode echocardiography. The rate-corrected mean velocity of fiber shortening (mVcfc)-end-systolic wall stress (ESS) relation was used as an index of contractility. There were significant inverse linear correlations between ESS and mVcfc in the three groups (all P<0.01). The slopes and y-intercepts of the regression lines of mVcfc-ESS relation were both significantly greater in the premature infants (mVcfc=-0.0133 ESS+1.62) and neonates (mVcfc=-0.0107 ESS+1.55) than those in the children (mVcfc=-0.0047+1.29). However, there were no significant differences between the premature and fullterm infants. Thus, these findings suggest that the contractility and afterload sensitivity of the left ventricle in the premature infants may be similar to those in the fullterm infants. In addition, our serial study in the premature infants showed that the ESS increased significantly with growth while the mVcfc did not change, suggesting that the left ventricular performance in the premature infants during early life was preserved in the setting of a lower afterload.