Paradoxical hypertension after repair of coarctation of the aorta: a review of its causes

Antihypertensive therapy of late arterial hypertension in children following successful coarctation correction

BACKGROUNG

Late arterial hypertension (AH) is the most significant complication of coarctation of the aorta (CoA). Only a few clinical studies described antihypertensive treatment of late AH following successful CoA repair. The primary objective of this multicentre cross-sectional study was to describe real-life antihypertensive therapy for late AH in children after hemodynamically successful CoA repair. The secondary objective was to describe antihypertensive therapy used within different haemodynamic phenotypes of AH.

METHOD

Blood pressure status, echocardiographic parameters and central blood pressure measurements were evaluated in 110 children aged 6-18 years following successful CoA repair with right arm blood pressure not exceeding leg blood pressure by at least 20 mmHg.

RESULTS

AH was found in 62 (56%) patients including 47 who were already treated and 15 with new diagnosed AH of whom seven presented with masked hypertension. Among treated patients, 10 presented with masked hypertension. The dominant phenotype of AH among patients with uncontrolled AH was isolated systolic hypertension (32 patients out of 37; 87.5%). AH was controlled in 53% of treated patients. Fifty-three percent of hypertensive patients had elevated central SBP and 39% had left ventricular hypertrophy with various left ventricle geometry patterns, 23% of them had both. β-adrenergic receptor blockers were the most used antihypertensive drugs followed by angiotensin-converting enzyme inhibitors with doses within the lower recommended range.

CONCLUSION

High prevalence of uncontrolled AH despite successful CoA repair and use of relatively low doses of antihypertensive drugs indicates the need of close blood pressure monitoring and more intensive and combined antihypertensive therapy.

Results of Coarctation Repair by Thoracotomy in Pediatric Patients: A Single Institution Experience

BACKGROUND

Aortic coarctation is among the most common cardiovascular congenital abnormalities requiring repair after birth. Besides mortality, morbidity remains an important aspect. Accordingly, we reviewed our 20-year experience of aortic coarctation repair by thoracotomy, with emphasis on both short- and long-term outcomes.

METHODS

From 1995 through 2014, 214 patients underwent coarctation repair via left thoracotomy. Associated arch lesions were distal arch hypoplasia (n = 117) or type A interrupted aortic arch (n = 6). Eighty-four patients had isolated coarctation (group 1), 66 associated ventricular septal defect (group 2), and 64 associated complex cardiac lesions (group 3). Median follow-up was 8.4 years.

RESULTS

There was one (0.5%) procedure-related death. Nine (4.2%) patients died during index admission. In-hospital mortality was 0.7% in group 1 and 2 and 12.5% in group 3 (P < .001). No patient had paraplegia. Actuarial five-year survival was 97.5% in group 1, 94% group 2 and 66% in group 3. Recurrent coarctation developed in 29 patients, all but four (1.8%) successfully treated by balloon dilatation. Freedom from reintervention (dilatation or surgery) at five years was 86%. At hospital discharge, 28 (13.5%) patients were hypertensive. At follow-up, hypertension was present in 11 (5.3%) patients.

CONCLUSIONS

Long-term results of aortic coarctation repair by thoracotomy are excellent, with percutaneous angioplasty being the procedure of choice for recurrences. Patient prognosis is dependent on associated cardiac malformations. In this study, the prevalence of late arterial hypertension was lower than previously reported.

Abdominal pain after stenting for aortic coarctation

A 56-year-old man underwent stenting for treatment of coarctation of the aorta. He subsequently developed severe abdominal pain and paradoxical postoperative hypertension. Abdominal computed tomography revealed two long mesenteric artery lesions. After potent antihypertensive therapy, he did not develop intestinal necrosis, and he was discharged with no recurrent abdominal pain. Although postcoarctectomy syndrome is rare in the current era of nonsurgical intervention for coarctation of the aorta, it can still occur and should be carefully managed to prevent intestinal necrosis.

Labetalol Infusion Attenuates Paradoxical Hypertension and Decreases Plasma Renin Activity After Repair of Coarctation of the Aorta in Children

OBJECTIVE

Paradoxical hypertension after repair of coarctation of the aorta in children is associated with the release of catecholamines and activation of the renin-angiotensin system. The objective of the present study was to describe the effects of labetalol infusion on blood pressure, plasma catecholamine levels, and plasma renin activity in a series of children undergoing repair of coarctation of the aorta.

DESIGN

Prospective, observational cohort study.

SETTING

Tertiary children's hospital with university affiliation.

PARTICIPANTS

The study was comprised of 15 consecutive children older than 1 year undergoing repair of coarctation of the aorta.

INTERVENTIONS

Intravenous infusion of labetalol, up to 20 µg/kg/min, was administered when patients became hypertensive after release of the aortic cross-clamp. Supplementation with nitroprusside was allowed as needed.

MEASUREMENTS AND MAIN RESULTS

Blood pressure was maintained below baseline values throughout the labetalol infusion. Plasma norepinephrine increased from 160 ± 81 pg/mL (preoperative) to 657 ± 268 pg/mL (6 h after release of aortic cross-clamp). Plasma renin activity decreased from 16.6 ± 9.7 ng/kg/h (at cross-clamp release) to 2.2 ± 2.2 ng/kg/h (6 h after cross-clamp release). Nitroprusside was added for 12 patients, at a highest mean dose of 2.4 ± 2.5 μg/kg/min.

CONCLUSIONS

Labetalol inhibited activation of the renin-angiotensin system and helped control paradoxical hypertension after coarctation repair in children.

Repaired coarctation of the aorta, persistent arterial hypertension and the selfish brain

BACKGROUND

It has been estimated that 20-30% of repaired aortic coarctation (CoA) patients develop hypertension, with significant cardiovascular morbidity and mortality. Vertebral artery hypoplasia (VAH) with an incomplete posterior circle of Willis (ipCoW; VAH + ipCoW) is associated with increased cerebrovascular resistance before the onset of increased sympathetic nerve activity in borderline hypertensive humans, suggesting brainstem hypoperfusion may evoke hypertension to maintain cerebral blood flow: the "selfish brain" hypothesis. We now assess the "selfish brain" in hypertension post-CoA repair.

METHODS

Time-of-flight cardiovascular magnetic resonance angiography from 127 repaired CoA patients (34 ± 14 years, 61% male, systolic blood pressure (SBP) 138 ± 19 mmHg, diastolic blood pressure (DBP) 76 ± 11 mmHg) was compared with 33 normotensive controls (42 ± 14 years, 48% male, SBP 124 ± 10 mmHg, DBP 76 ± 8 mmHg). VAH was defined as < 2 mm and ipCoW as hypoplasia of one or both posterior communicating arteries.

RESULTS

VAH + ipCoW was more prevalent in repaired CoA than controls (odds ratio: 5.8 [1.6-20.8], p = 0.007), after controlling for age, sex and body mass index (BMI). VAH + ipCoW was an independent predictor of hypertension (odds ratio: 2.5 [1.2-5.2], p = 0.017), after controlling for age, gender and BMI. Repaired CoA subjects with VAH + ipCoW were more likely to have difficult to treat hypertension (odds ratio: 3.3 [1.01-10.7], p = 0.049). Neither age at time of CoA repair nor any specific repair type were significant predictors of VAH + ipCoW in univariate regression analysis.

CONCLUSIONS

VAH + ipCoW predicts arterial hypertension and difficult to treat hypertension in repaired CoA. It is unrelated to age at time of repair or repair type. CoA appears to be a marker of wider congenital cerebrovascular problems. Understanding the "selfish brain" in post-CoA repair may help guide management.

JOURNAL SUBJECT CODES

High Blood Pressure; Hypertension; Magnetic Resonance Imaging (MRI); Cardiovascular Surgery; Cerebrovascular Malformations.

Epidurals for Coarctation Repair in Children Are Associated with Decreased Postoperative Anti-Hypertensive Infusion Requirement as Measured by a Novel Parameter, the Anti-Hypertensive Dosing Index (ADI)

Background: Sympathetically-associated hypertension after coarctation repair is a common problem often requiring anti-hypertensive infusions in an intensive care unit. Epidurals suppress sympathetic output and can reduce blood pressure but have not been studied following coarctation repair in children. We sought to determine whether epidurals for coarctation repair in children were associated with decreased requirement for postoperative anti-hypertensive infusions, if they were associated with changes in hospital course, or with complications. Methods: In this observational retrospective cohort study, we evaluated all patients age 1–18 years undergoing coarctation repair at our institution during a 10-year period and compared the requirement for postoperative anti-hypertensive infusions in patients with and without epidurals using an anti-hypertensive dosing index (ADI) incorporating total dose-hours of all anti-hypertensive infusions (primary outcome). We also assessed intensive care unit (ICU) and hospital length of stay, discharge on oral anti-hypertensive medication, and complications potentially related to epidurals (secondary outcomes). Results: Children undergoing coarctation repair with epidurals had decreased requirements for postoperative anti-hypertensive infusions compared to children without epidurals (cumulative ADI 65.0 [28.5–130.3] v. 157.0 [68.6–214.7], p = 0.021; mean ADI 49.0 [33.3–131.2] v. 163.0 [66.6–209.8], p = 0.01). After multivariable cumulative logit mixed-effects regression analysis, mean ADI was decreased in patients with epidurals throughout the postoperative period (p < 0.001). Patients with epidurals were 1.6 years older and weighed 10.6 kg more than patients without epidurals but were otherwise comparable. Epidural complications included pruritus (three patients), agitation (one patient), somnolence (one patient), and transient orthostatic hypotension (one patient). Duration of intensive care unit admission, duration of hospital stays, and requirement for anti-hypertensive medication at discharge were similar in patients with and without epidurals. Conclusions: This is the first study of children receiving an epidural for surgical repair of aortic coarctation via open thoracotomy. In this small, single-institution, observational retrospective cohort study, epidurals for coarctation repair in children were associated with decreased postoperative anti-hypertensive infusion requirements. Epidurals were not associated with length of ICU or hospital stay, or with discharge on anti-hypertensive medication. No significant epidural complications were noted. Prospective study of larger populations will be necessary to confirm these associations, address causality, verify safety, and assess other effects.

Assessment the effect of dexmedetomidine on incidence of paradoxical hypertension after surgical repair of aortic coarctation in pediatric patients

OBJECTIVE

The aim of the study was to assess the effect of dexmedetomidine on the incidence of paradoxical hypertension in patients undergoing aortic coarctation repair.

DESIGN

Randomized observational study.

SETTING

University hospital and cardiac center.

PATIENTS

The study included 108 pediatric patients with isolated aortic coarctation.

METHODS

The patients were classified into two groups (each = 54): Group D: the patients received dexmedetomidine as a loading dose of 0.5 μg/kg over 10 min followed by infusion 0.3 μg/kg/h during surgery and continued for the first 48 postoperative hours. Group C: The patients received an equal amount of normal saline. The medication was prepared by the nursing staff and given to anesthetist blindly. The collected data included the heart rate, systolic and diastolic arterial blood pressure, incidence, onset, severity and treatment of paradoxical hypertension, fentanyl dose and end-tidal sevoflurane concentration, amount of blood loss and urine output.

MAIN RESULTS

The heart rate, systolic and diastolic blood pressure decreased significantly with dexmedetomidine than Group C (P < 0.05). The incidence and severity of the paradoxical hypertension was lower with dexmedetomidine than Group C (P = 0.011, P = 0.017, respectively). The onset the paradoxical hypertension was earlier in Group C than dexmedetomidine (P = 0.026). The dose of fentanyl and sevoflurane concentration decreased significantly with dexmedetomidine (P = 0.034, P = 0.026, respectively). The blood loss decreased with dexmedetomidine (P = 0.020) and the urine output increased with dexmedetomidine (P = 0.024). The incidence of hypotension and bradycardia was more with dexmedetomidine (P < 0.05).

CONCLUSION

Dexmedetomidine is safe in pediatric patients undergoing aortic coarctation repair. It minimized the incidence and severity of paradoxical hypertension. It decreased the required antihypertensive medications.

Treatment Strategies for Paradoxical Hypertension Following Surgical Correction of Coarctation of the Aorta in Children

BACKGROUND

Paradoxical hypertension after repair of coarctation of the aorta is a well-known phenomenon. The pathogenesis involves the activation of the sympathetic nervous system (first phase) and renin-angiotensin system (second phase). Only a limited number of different treatment strategies have been published in the literature, without any comparative studies.

METHODS

Our aim was to describe the current international practice variation surrounding pharmacological treatment currently being employed to treat paradoxical hypertension following the repair of coarctation of the aorta in children. We performed an online survey among 197 members of the Pediatric Cardiac Intensive Care Society. We also conducted a systematic review of the literature regarding the treatment of paradoxical hypertension.

RESULTS

Eighty-eight people (45%), from 62 different centers, responded and answered the questions regarding blood pressure control. Nitroprusside is the first drug of choice for initial blood pressure control in 66% of respondents, esmolol in 11%, labetalol in 11%, and angiotensin-converting enzyme inhibitors (ACEIs) are used by 3% of respondents. For oral blood pressure control after discharge from the pediatric intensive care unit, 75% of respondents use ACEIs, 18% use labetalol, and 12% use other beta-blockers (propranolol, carvedilol, atenolol, metoprolol). The systematic review identified 14 articles reporting pharmacological treatment of direct postoperative hypertension following coarctation repair.

CONCLUSION

There is wide practice variability, due to the lack of sufficient compelling evidence. The majority (66%) of caregivers use nitroprusside to control blood pressure in the acute postoperative phase. The ACEIs are the drug of choice for chronic blood pressure control.

Aortic Coarctation: Anesthetic Considerations

Aortic coarctation is a congenital narrowing of the descend ing thoracic aorta at or near the connection of the ductus arteriosus. It is the sixth most common congenital heart disease in the pediatric age group and constitutes 8% of congenital heart anomalies. Delivering anesthesia care to children undergoing coarctation repair is challenging be cause the anesthetist and the surgeon do not have the immediate safety net provided by cardiopulmonary bypass. Once the aorta is cross-clamped and the repair begins, the anesthesiologist is at the mercy of the surgeon's technical skill and speed and the child's ability to tolerate aortic cross- clamping. This article addresses the etiology and morphol ogy of this lesion. In addition, the perioperative anesthetic management principles relating to coarctation repair are discussed.

Use of dexmedetomidine as an adjunct in the treatment of paradoxical hypertension after surgical repair of coarctation of the aorta in infants

Severe persistent hypertension is seen infrequently in newborns and infants, but we came across two infants who developed severe paradoxical hypertension after successful coarctation repair. Treatment of systemic hypertension following repair of coarctation of the aorta is always challenging particularly in infants. Dexmedetomidine was used successfully as an adjunct to the established anti-hypertensive drugs in the immediate postoperative period in our cases to treat postoperative paradoxical hypertension.

Coarctation of the aorta in adolescents and adults: A review of clinical features and CT imaging

Coarctation of the aorta (CoA), while usually identified and treated in the neonatal/infant period, is increasingly seen in adults, either primarily or (more often) following repair. Imaging plays a crucial role in the diagnosis, therapeutic planning, and follow-up of patients with CoA. Clinical management of CoA in adults optimally involves a multidisciplinary team; accordingly, imagers should be familiar with the underlying pathology, associations, and management of CoA in addition to imaging protocoling and interpretation. We will review the relevant clinical and imaging features of CoA, with an emphasis on patients beyond childhood.

The safety, efficacy, and pharmacokinetics of esmolol for blood pressure control immediately after repair of coarctation of the aorta in infants and children: a multicenter, double-blind, randomized trial

OBJECTIVES

Blood pressure control is important after repair of coarctation of the aorta. We report the first prospective multi-institutional trial addressing the safety and efficacy of esmolol after repair of coarctation of the aorta in infants and children.

METHODS

The primary objective of this phase IIIb, multicenter, double-blind, randomized, dose-ranging trial was the efficacy of esmolol to control hypertension. Candidates included subjects younger than 6 years and weighing 2.5 kg or more who underwent surgical intervention for coarctation of the aorta and required therapy for systemic hypertension. One hundred sixteen subjects received esmolol: 36 received a low dose (125 microg/kg), 43 received a medium dose (250 microg/kg), and 37 received a high dose (500 microg/kg). The primary outcomes were the change in systolic blood pressure and the need for additional antihypertensive rescue medication 5 minutes after the initiation of esmolol.

RESULTS

All dose groups showed a significant decrease from baseline in systolic blood pressure (-9.6 +/- 16.3 mm Hg, P < .001). There were no differences in systolic blood pressure response at 5 minutes between dose groups (high, medium, or low) or age groups. The need for rescue medication at 5 minutes was not different between dose groups. All dose groups showed similar incidences of adverse events. There were no serious adverse events.

DISCUSSION

Esmolol can be administered safely to patients younger than 6 years after repair of coarctation of the aorta. In the dose range of 125 to 500 microg/kg, esmolol significantly decreased systolic blood pressure.

Severe labetalol overdose in an 8-month-old infant

We report a case of a large labetalol overdose in an eight-month-old infant that was being treated for hypertension following surgery for coarctation of the aorta. Labetalol, both alpha and beta adrenergic blocking agent was used for treating postoperative hypertension. By mistake, the patient was given an extremely high dose of labetalol intravenously (17.2 mg.kg(-1)). Remarkably, the medication error had a surprisingly limited clinical effect on the infant who survived the incident. We discuss the pharmacokinetic, pharmocodynamic and possible explanations for this fortunate turn of events.

Comparison of surgical and transcatheter treatment for native coarctation of the aorta in patients > or = 1 year old. The Quebec Native Coarctation of the Aorta study

BACKGROUND

The objectives of this study were to compare, in the current era, the immediate results, complications, and midterm outcomes obtained by surgical repair versus transcatheter treatment of coarctation of the aorta (CoA).

METHODS

The study was of retrospective nature and included 80 consecutive patients > or = 1 year old (mean age 12 +/- 10 years) treated for an isolated CoA in 4 university centers in Quebec between 1998 and 2004. Fifty patients underwent aortic angioplasty, with stent implantation in 19, and 30 had surgical repair. Immediate results, procedural complications, clinical events, and the incidence of aortic aneurysm at follow-up were compared between groups.

RESULTS

There were no differences between the 2 groups in clinical baseline characteristics. Percentage reduction in peak systolic pressure gradient across the coarctation was similar between the 2 groups (angioplasty 72% +/- 23% vs surgery 75% +/- 18%, P = .55). Procedure-related complications occurred more frequently after surgical repair compared with angioplasty (50% vs 18%, P = .005), and median hospitalization time was longer in the surgical than in the angioplasty group (7 vs 1 day, P < .001). At 38 +/- 21 months' follow-up, no patient in the surgical group and 16 patients in the angioplasty group had at least 1 aortic reintervention (0% vs 32%, P < .0001). The presence of an aortic aneurysm was diagnosed more frequently in the angioplasty group compared with the surgical group (24% vs 0%, P = .01).

CONCLUSION

Aortic angioplasty provided comparable immediate hemodynamic results to surgery, with reduced morbidity and hospitalization length for the treatment of CoA in patients > or = 1 year old. However, angioplasty was associated with a higher rate of reintervention and aneurysm formation at a mean follow-up of 3 years.

Evidence of vascular dysfunction in young patients with successfully repaired coarctation of aorta

It is well documented that in patients with coarctation of the aorta life expectancy is not normal even after successful coarctation repair (SCR), primarily due to cardiovascular events. We examined endothelial function in the forearm circulation, the mechanical properties and intima/media thickness in carotid and femoral arteries and the inflammatory process in normotensive patients, after coarctation repair. Fifteen patients, 29+/-2 years old, 12+/-2.9 years after SCR and 16 age- and sex-matched controls were enrolled in our study. Forearm blood flow was determined by gauge-strain plethysmography. Forearm vasodilatory response to reactive hyperemia was expressed as the %change from baseline to post-reactive hyperemia blood flow. High resolution ultrasound was used for determination of intima/media thickness and elastic properties of carotid and femoral arteries. Serum levels of soluble vascular adhesion molecule 1 (sVCAM-1), intercellular adhesion molecule 1 (sICAM-1), E-selectin, and interleukines 1b (IL-1b) and 6 (IL-6) were determined by ELISA. Reactive hyperemia was significantly decreased in patients compared to controls (p<0.01). Patients with SCR had higher intima/media thickness and decreased distensibility in the carotid arteries than controls (p<0.01 for both). Serum levels of sICAM-1, sSVCAM-1, E-selectin and IL-1b were higher in SCR group than in controls (p<0.05 for all). Adult patients after SCR have impaired endothelial function in the forearm circulation, increased intima/media thickness, decreased distensibility in the carotid arteries and increased levels of proinflammatory cytokines and adhesion molecules than healthy controls. These results may partly explain the high incidence of coronary artery disease in patients with repaired coarctation of the aorta.

Diagnosis and treatment of hypertension in children and adolescents

PURPOSE

To provide nurse practitioners (NPs) with updated information regarding the etiology, diagnosis, and treatment of childhood hypertension.

DATA SOURCES

Extensive review of the scientific literature regarding hypertension, including the latest NIH recommendations.

CONCLUSIONS

Hypertension affects more than 350,000 American children. While the majority of hypertension in early childhood occurs from secondary causes, the incidence of essential hypertension in later childhood and adolescence is rising, raising concerns as elevated pressures in childhood "track" into adulthood. Early detection and treatment of elevated childhood pressures represent important steps in reducing long-term cardiovascular risk.

IMPLICATIONS FOR PRACTICE

NPs must be able to accurately differentiate between primary and secondary hypertension in childhood. Secondary hypertension requires prompt diagnosis and treatment, and controlling primary childhood hypertension has lifelong implications. Given the familial predisposition to hypertension, it is important for adult NPs to be aware of the risks faced by children of hypertensive patients.

Coarctation of the aorta

Controversy still exists in the literature regarding definitive therapy for repair of coarctation of the aorta. Major factors involve not only the timing of repair, but also the method of repair, whether surgical or by percutaneous transluminal balloon dilatation. Results and complications of coarctation repair using various methods of classification present a diversity of results. This report will focus on these issues and attempt to dispel the statement that either one method or the other is the "choice method" of repair for any and all types of coarctation. Also presented is a proposed classification we believe will assist in clarifying the choice of therapy and perhaps improve not only the reporting of results, but also the results themselves. Methods of repair are discussed to provide the surgeon with a complete armamentarium of operations that the surgeon would tailor to the individual anatomicopathological patterns of the patient who presents at the time of surgery. Copyright 2000 by W.B. Saunders Company

Will Camp Sealy: surgical innovator, scholar, exceptional teacher, and true Georgian

Will Camp Sealy, MD, Professor Emeritus of Surgery, Duke University 1984 and Mercer University 1992, was born in Roberta, Georgia, in 1912. A 1936 medical graduate of Emory University, he was in surgical residency training at Duke University from 1936 to 1942. During the next 4 years as an army surgeon in World War II, he was promoted to lieutenant colonel and, in the European theater, made chief of surgery of the 121st General Hospital and later the 128th Evacuation Hospital. After the war, he rejoined the surgical faculty at Duke. In 1950, he became chairman of the division of thoracic and cardiovascular surgery, where in the ensuing years he made a number of important initial observations and significant contributions. Among these were studies on the serious paradoxical hypertension that may follow repair of coarctation of the aorta, and on the combined use of hypothermia and perfusion for open heart surgical procedures. In more recent years, his initiation and landmark studies of the surgical treatment of certain cardiac arrhythmias have gained him worldwide recognition and opened one of the last frontiers of cardiac surgery.