Prevalence of migraine headaches in patients with congenital heart disease.

The prevalence of migraine headaches (MH) is 12% in the general population and increases to 40% in patients with patent foramen ovale. This study evaluated the prevalence of MH in patients with congenital heart disease (CHD). Of 466 patients contacted from the UCLA Adult Congenital Heart Disease Center, 395 (85%) completed a questionnaire to determine the prevalence of MH. Patients were stratified by diagnosis of right-to-left, left-to-right, or no shunt. A group of 252 sex-matched patients with acquired cardiovascular disease served as controls. The prevalence of MH was 45% in adults with CHD compared to 11% in the controls (p<0.001). Of the 179 patients with MH, 143 (80%) had migraines with aura and 36 (20%) had migraines without aura versus 36% and 64% observed in the controls (p<0.001). The frequency of MH was 52% in the right-to-left shunt group, 44% in the left-to-right, and 38% in the no shunt group (p=NS). In patients with a right-to-left shunt who underwent surgical repair, 47% had complete resolution of MH, whereas 76% experienced >50% reduction in headache days per month. In conclusion, the prevalence of MH in all groups of adults with CHD is 3 to 4 times more than a sex-matched control population, with increasing prevalence of MH in patients with no shunt, left-to-right, and right-to-left shunt. The higher than expected frequency of MH in patients with CHD without an intracardiac shunt, suggests additional mechanisms to explain the significant association with MH.

The coronary microcirculation in cyanotic congenital heart disease.

BACKGROUND: Despite an appreciable increase in basal coronary blood flow in cyanotic congenital heart disease, flow reserve remains normal. We hypothesized that preservation of flow reserve resides in remodeling of the coronary microcirculation. Microcirculatory morphometric analyses were performed to test this hypothesis. METHODS AND RESULTS: Necropsy specimens from 4 sources were studied: (1) hearts from patients with Eisenmenger's syndrome (A; n=5), (2) structurally abnormal hearts with ventricular hypertrophy (B; n=8), (3) structurally normal hearts with ventricular hypertrophy (C; n=6), and (4) normal hearts (D; n=5). To compare responses of the microcirculation to hypoxia versus hypertrophy, sections were taken from the left ventricular free wall, which in group A, was hypoxemic but not hypertrophied; in groups B and C, was hypertrophied but not hypoxemic; and in group D, was neither hypertrophied nor hypoxemic. Coronary arterioles were immunolabeled for smooth muscle alpha-actin. Measured morphometric parameters included long and short axes, area, and perimeter. Arteriolar length, volume and surface densities were calculated. There was a significant intergroup difference for arteriolar length density (P=0.03) and diameter (P=0.03). Total length density in group A hearts was markedly lower, but mean arteriolar diameter was significantly greater (34%) compared with group B (P=0.03). Arteriolar volume density was similar to that in the other groups. CONCLUSIONS: Remodeling of the coronary microcirculation is the key mechanism for preservation of flow reserve in cyanotic congenital heart disease. The increase in short axis (diameter) compensated for lower arteriolar length density and was the principal anatomic basis for maintenance of normal flow reserve.

Nitric oxide metabolism in adults with cyanotic congenital heart disease.

Endothelial-derived nitric oxide (NO) diffuses abluminally to regulate blood flow by activating soluble guanylate cyclase in medial smooth muscle. However, a significant fraction of NO diffuses luminally, where the extremely high reaction rate with red blood cell hemoglobin (Hb) effectively reduces luminal concentration to zero. The erythrocytosis of cyanotic congenital heart disease has potentially opposing effects, namely, a reduction in medial smooth muscle NO bioavailability because of the increase in luminal consumption of the molecule and, conversely, an increase in the elaboration of NO in response to the high endothelial shear stress of the erythrocytotic perfusate. NO metabolism in cyanotic congenital heart disease is unknown. Accordingly, this study aimed to establish the metabolic fate of NO and to determine the degree to which its levels are altered. Blood samples from 25 nonfasting patients with cyanotic congenital heart disease and 25 nonfasting normal controls were collected in Vacutainer tubes containing citrate dextrose and in separate Vacutainer tubes containing a solution that specifically preserves S-nitrosated Hb. Total NO species, plasma S-nitrosated proteins, iron nitrosyl Hb, and S-nitrosated Hb were quantified using chemiluminescence. In conclusion, a significant increase in plasma concentrations of NO metabolites and a modest increase in iron nitrosyl Hb levels were found, suggesting increased luminal consumption caused by erythrocytosis and further suggesting that hypoxemia might activate nonoxidative NO metabolic pathways and enhance tissue oxygen delivery.

Pulmonary neovascularity: a distinctive radiographic finding in Eisenmenger syndrome.

BACKGROUND: We sought to characterize the distinctive pulmonary vascular abnormalities seen on chest radiographs and computed tomography (CT) scans in Eisenmenger syndrome. METHODS AND RESULTS: Thoracic CT scans, chest radiographs, and clinical data were reviewed for 24 Eisenmenger syndrome patients subdivided into those with interatrial (pretricuspid) versus interventricular or great arterial (posttricuspid) communications and in 14 acyanotic patients with pulmonary arterial hypertension (PAH) and no congenital heart disease. CT scans were scored blindly by 2 thoracic radiologists for the presence and severity of small, tortuous, intrapulmonary vessels, termed "neovascularity," lobular ground-glass opacification, and systemic perihilar and intercostal vessels. Histopathologic lung sections from 5 patients with Eisenmenger syndrome and from 3 patients with acyanotic PAH were reviewed. Associations between clinical and imaging features were tested by ANOVA and chi2 tests. Kendall's rank-order coefficient and the Kruskal-Wallis test were used to test for significant differences in imaging features between Eisenmenger syndrome and acyanotic PAH. Neovascularity on chest radiographs was more common in Eisenmenger syndrome than acyanotic PAH, but differences were not significant. On CT, neovascularity, lobular ground-glass opacification, and hilar and intercostal systemic collaterals were more prevalent in Eisenmenger syndrome, with severity greater in posttricuspid communications. Three previously undescribed vascular lesions were identified histologically in Eisenmenger syndrome: malformed, dilated, muscular arteries within alveolar septa; congested capillaries within alveolar walls; and congested capillaries within the walls of medium-size, muscular pulmonary arteries. These lesions may correspond to the distinctive vascular abnormalities observed on chest radiographs and CT scans. CONCLUSIONS: Distinctive vascular lesions on chest radiographs and CT scans in Eisenmenger syndrome appear to be correlated histologically with collateral vessels that develop more extensively with posttricuspid communications.

Pathogenesis of thrombocytopenia in cyanotic congenital heart disease.

Although a significant minority of patients with cyanotic congenital heart disease (CCHD) are thrombocytopenic, the pathogenesis and prevalence have not been established. This study was designed to address these 2 issues. We included 105 patients with CCHD (60 men and 45 women; aged 21 to 54 years). Systemic arterial oxygen saturations were 69% to 78%. Hematocrits were 62% to 74% with normal iron indexes. In 26 of 105 patients (25%), platelet counts were <100x10(9)/L. The diagnosis was Eisenmenger syndrome in all 26 patients with thrombocytopenia. Platelet production was determined by flow cytometric reticulated platelet counts. Megakaryocyte mass was determined indirectly by thrombopoietin levels. Disseminated intravascular coagulation was based on prothrombin time, activated partial thromboplastin time, and D-dimers. Platelet activation was determined by levels of platelet factor 4 and beta thromboglobulin. Reference ranges were derived from 20 normal acyanotic controls. A reduction in absolute reticulated platelet counts implied decreased platelet production (p<0.001). Normal thrombopoietin levels implied normal megakaryocyte mass. Normal prothrombin time, activated partial thromboplastin time, and D-dimers excluded disseminated intravascular coagulation. Normal platelet factor 4 and beta thromboglobulin indicated absent or minimal platelet activation. Twenty-five percent of the patients with CCHD were thrombocytopenic because platelet production was decreased despite normal megakaryocyte mass. We hypothesized that right-to-left shunts deliver whole megakaryocytes into the system arterial circulation, bypassing the lungs where megakaryocytic cytoplasm is fragmented into platelets, thus reducing platelet production. In conclusion, platelet counts in CCHD appear to represent a continuum beginning with low normal counts and ending with thrombocytopenia.

Usefulness of post-ventriculotomy signal averaged electrocardiograms in congenital heart disease.

Signal-averaged electrocardiography is a sensitive and specific technique for detecting the slow conduction electrophysiologic substrates of reentrant monomorphic ventricular tachycardia. Although well established, the method has not been used for electrophysiologic assessment after right ventriculotomy for the intracardiac repair of congenital heart disease. This 8-year prospective study provided this assessment. Recordings were obtained from 242 post-ventriculotomy patients with congenital heart disease aged 16 to 72 years (139 males, 103 females). Because ventricular volume or pressure overload can prolong the QRS duration, 40 unoperated patients with hemodynamic overload served as controls. Orthogonal X, Y, and Z body surface electrodes were used to detect ventricular late potentials by permitting the examination of portions of the electrocardiogram otherwise obscured by noise and artifacts. Positive signal-averaged electrocardiographic (SAECG) results were based on established criteria derived from 3 time-domain variables calculated by an automated algorithm. Late potentials were detected in 151 of 242 patients (62%) and were significantly higher than controls (p = 0.0001). Radiofrequency ablation of an inducible slow conduction substrate rendered 20 of 23 positive post-ventriculotomy SAECG results negative, and surgical revision of the ventriculotomy scar rendered 19 of 19 positive SAECG results negative. In conclusion, negative SAECG results connote the absence of a reentrant substrate, and therefore, the absence of risk for reentrant monomorphic ventricular tachycardia, whereas positive SAECG results connote the presence of a slow conduction substrate and the potential risk for monomorphic ventricular tachycardia.

Cyanotic congenital heart disease and coronary artery atherogenesis.

Hypoxemic erythrocytotic residents of high altitudes lack coronary atherosclerosis and have low cholesterol levels. It was postulated that hypoxemic erythrocytotic adults with cyanotic congenital heart disease (CCHD) might be analogous. The incidence of coronary atherosclerosis in this patient population has not been established, and hypocholesterolemia has not previously been recognized. Accordingly, 279 patients were divided into 4 groups: group A: 143 cyanotic patients not operated on (54 men and 89 women, aged 18 to 69 years); group B: 47 cyanotic patients (28 men and 19 women rendered acyanotic by operation at age 22 to 69 years); group C: 41 acyanotic patients not operated on (22 men and 19 women, aged 22 to 75 years); and group D: 48 patients acyanotic before and after operation (24 men and 24 women, aged 21 to 70 years). Coronary arteries were studied angiographically in 59 patients and at necropsy in 5 subjects aged 37 to 56 years. Total cholesterol was <160 mg/dl in 58% of group A, 52% of group B, 10% of group C, and 12% of group D (p <0.000001, chi-square analysis). Angiograms disclosed dilated coronary arteries without obstruction. Necropsy disclosed ectatic coronary arteries with structural abnormalities of the media. In conclusion, this study provides the first quantitative and qualitative data on antiatherogenic changes in lipoproteins in adults with CCHD. The coronary arteries are atheroma free because hypocholesterolemia acts in concert with the antiatherogenic properties of upregulated nitric oxide, hyperbilirubinemia, hypoxemia, and low platelet counts. The persistence of hypocholesterolemia after the surgical elimination of cyanosis suggests a genetic determinant.

Gynecological health of females with congenital heart disease.

Because of major advances in diagnostic and surgical methods, females with congenital heart disease (CHD) now survive into and beyond their reproductive years. Management of pregnancy in this patient population is well described, but gynecologic management such as menstruation, contraception and menopause have received scanty attention. Accordingly, the gynecologic health issues confronting these patients are described. Menstrual patterns in acyanotic females with CHD are similar to the general population, but cyanotic females have menstrual irregularities including amenorrhea, which implies anovulation and an increased risk of uterine carcinoma. Anticoagulants predispose to heavy vaginal bleeding and corpus luteum rupture. Contraceptives must be selected according to individual patient profiles. Hormone replacement therapy is warranted for relief of menopausal symptoms as in the general population and should be relatively safe because estrogen dose is low.

Surgical treatment of patent ductus arteriosus: a new historical perspective.

The conventional surgical history of ligation of a patent ductus arteriosus (PDA) dates from August 26, 1938, when Robert E. Gross of Boston, Massachusetts, successfully ligated a PDA. It is largely unknown that in the same year and before Gross, Emil Karl Frey, a Surgeon at the Medizinische Akademie in Dusseldorf, Germany, already ligated a PDA successfully. Assuming that he would soon perform more ligations, Frey did not publish his findings, and this historic ductal operation escaped attention.

Extramural coronary arteries in adults with cyanotic congenital heart disease.

Dilatation and tortuosity of extramural coronary arteries are prevalent in cyanotic congenital heart disease. Two pathogenetic variables are operative, namely endothelial vasodilator substances and medial structural abnormalities.

Proximal pulmonary arterial and intrapulmonary radiologic features of Eisenmenger syndrome and primary pulmonary hypertension.

Extrapulmonary and intrapulmonary radiologic features of Eisenmenger syndrome and primary pulmonary hypertension (PPH) and the clinical expressions that coincide with the radiologic features of these 2 forms of pulmonary hypertension have not previously been characterized. Computed tomography (CT) and pulmonary CT angiography (CTA) utilized GE High Speed Advantage or Siemens Evolution electron beam tomographic (EBT) scanners in 31 patients with cyanotic pulmonary vascular disease (PVD) (group A: 12 men and 19 women; mean age 38 +/- 4 years) and in 13 women with PPH-acyanotic PVD (group B: mean age 30 +/- 3 years). Ten group A and 3 group B patients underwent imaging twice, yielding 57 studies. Group A patients' extrapulmonary radiologic features included proximal pulmonary arteries that were consistently enlarged, and were aneurysmal in 13%, causing bronchial compression and atelectasis. Thromboses were uniformly present and mild in 71% and moderate to massive in 29% of patients. Massive proximal thromboses caused asphyxic death and augmented right-to-left shunts by increasing flow resistance. Mild to extensive mural calcific deposits occurred in 26% of patients. Intrapulmonary radiologic features included intrapulmonary embolic infarction, intrapulmonary hemorrhage, bronchial/systemic arterial collaterals, and neovascularity. Group B patients' extrapulmonary radiologic features included proximal pulmonary arteries that were consistently enlarged but not aneurysmal and devoid of thromboses. Mild to extensive mural calcific deposits occurred in 23% of these patients. Intrapulmonary radiologic features were confined to mosaic attenuation and bronchial/systemic collaterals.

Signal-averaged electrocardiogram in Ebstein's anomaly.

We sought to establish pathogenetic links between electrophysiology, histopathology, and ventricular tachyarrhythmias in patients with Ebstein's anomaly. The atrialized right ventricle (ARV) is the site of mechanically inducible ventricular tachyarrhythmias, but relations between the arrhythmogenic substrate, the type of tachyarrhythmias, and the trigger(s) have not been established. This study comprised 23 patients (10 men and 13 women; aged 18 to 58 years; mean 32 +/- 3) who did not undergo surgery and 6 pre- and postoperative patients with Ebstein's anomaly, diagnosed by transthoracic and transesophageal echocardiography. Twenty-one patients had classic Ebstein's anomaly and 2 had mild forms. Signal-averaged electrocardiograms (SAECGs) identified slow conduction by using 3 time-domain variables calculated by an automated algorithm and inspected visually. Two variables were required to establish the presence of late potentials. SAECGs were repeated in 6 patients after surgical exclusion of the ARV. Five surgical specimens of the ARV and the true right atrium were examined histologically. Mathematic simulations were used to illustrate anchored and unanchored spiral/scroll waves. SAECGs were positive in 21 patients with classic Ebstein's anomaly and were negative postoperatively in the 6 so studied. The ARV was characterized histologically by clusters of cardiomyocytes isolated within a fibrous matrix. We hypothesize that SAECGs identify slow conduction residing in the ARV, and that excitation of this arrhythmogenic substrate provokes spiral/scroll waves that cannot anchor because clusters of cardiomyocytes are isolated within a fibrous matrix. The waves meander erratically as polymorphic ventricular tachycardia or break up into ventricular fibrillation.

The coronary circulation in cyanotic congenital heart disease.

BACKGROUND: Dilated coronary arteries, coronary blood flow, and the paucity of coronary atherosclerosis have not been studied in cyanotic congenital heart disease. METHODS: Coronary arteriograms were interpreted in 59 cyanotic adults, and dilated coronaries were examined histologically in 6. Coronary blood flow was determined with N-13 ammonia positron emission tomography in 14 Eisenmenger syndrome patients and in 10 controls. Total non-fasting cholesterols were retrieved in 279 patients who were divided into: Group A--143 cyanotic unoperated, Group B--47 acyanotic after operation, Group C--41 acyanotic unoperated, Group D--48 acyanotic before and after operation. Total cholesterol was <160 mg/ml in 58% of Group A and 51% of Group B. Low- (LDL) and high-density cholesterol (HDL) and triglycerides were determined in 57/82 hypocholesterolemic patients. Platelet counts were determined in 105 patients. Platelet production, megakaryocyte production, platelet destruction, and platelet activation were studied. RESULTS: Angiography--88% of extramural coronary arteries were mildly or moderately dilated to ectatic and tortuous. Loss of medial smooth muscle, increased medial collagen, and duplication of internal elastic lamina were identified histologically. Basal coronary flow was increased, but hyperemic flow following IV dipyridamole was comparable in patients and controls. Atherosclerosis was not detected in either the arteriograms or the necropsy specimens. Thrombocytopenic resulted from reduced platelet production. CONCLUSIONS: Coronary arteries in cyanotic congenital heart disease dilate in response to endothelial vasodilators coupled with mural attenuation caused by medial abnormalities. Basal flow was increased, but flow reserve was normal. Coronary arteries were atheroma-free.

Survey of specialized tertiary care facilities for adults with congenital heart disease.

BACKGROUND: Specialized tertiary care facilities developed in response to the increasing numbers of adults with congenital heart disease (CHD). Because this patient population comprises a relatively new area of specialized cardiovascular interest, the first facilities necessarily evolved without preexisting guidelines or interaction. OBJECTIVES: To characterize the major features of the six original and largest tertiary adults CHD facilities. METHODS: Written questionnaire sent to six participating facilities in North America and Europe. Information was analyzed centrally. RESULTS: All but one facilities was established over 20 years ago, and each cares for over 1500 patients. Hospital admissions ranged from 100 to 660 patients/unit/year. Of the total number of registered patients, 52-81% had undergone one or more reparative surgeries. Reoperations constituted 25-80% of the 50-170 operations/unit/year. Overall mean surgical mortality was 1.9%/year. Inpatient and outpatient care was provided in adult (n = 4) or both adult and pediatric (n = 2) settings. All six facilities enjoyed close collaboration between adult and pediatric cardiologists, cardiac surgeons, nurse specialists and cardiac and non-cardiac consultants. Training and research were pivotal activities. CONCLUSIONS: Provision of comprehensive care by multidisciplinary teams including adult and pediatric cardiologists, cardiac surgeons, specialized nurses and other cardiac and non-cardiac consultants was the unifying feature for all six tertiary care facilities reported here. There were minor differences among them based on available resources, local expertise and national health care policies. There appears to be a significant shortfall in tertiary care provision for the adult with CHD that requires further planning and resource allocation. These data may be useful for new and evolving adult CHD services.

The Howard Gilman Foundation Lecture. Where have we come from and where are we going? Valve management past, present and future.

Leonardo da Vinci's anatomical drawings of quadricuspid, tricuspid, and bicuspid aortic valves underscored the hydraulic superiority of a three leaflet valve with cuspal equality. William Harvey demonstrated that venous valves were designed for unidirectional flow and to prevent reflux from the heart, observations that served as the basis of his immortal de Mortu Cordis. Joseph Rouanet of Paris proposed that heart sounds originated from the closing movements of cardiac valves. The Cardiodynamics of Mitral Insufficiency by Wiggers and Feil was followed three decades later by Paul Wood's An Appreciation of Mitral Stenosis. The Bland/Sweet operation indirectly addressed mitral stenosis by means of a venous shunt. Sir Henry Souttar's early digital repair of mitral stenosis was later reintroduced independently by Harken and Bailey; Doyen, Sellers, and Brock employed surgical valvotomy for pulmonary stenosis, and Bailey employed surgical valvotomy for aortic stenosis. Management of abnormal cardiac valves includes repair (reconstruction), replacement with mechanical or biologic prostheses, and interventional catheterization. The first mechanical valve was inserted extracardiac by Hufnagel into the descending thoracic aorta of patients with severe aortic regurgitation. The Starr caged ball mechanical prosthesis was designed for intracardiac replacement of an abnormal cardiac valve. The peripheral flow ball valve was followed by hydraulically superior and less thrombogenic central flow monoleaflet or bileaflet mechanical valves, and by homograft and heterograft bioprosthetic valves. Improved methods of preparing exogenous bioprostheses and innovative techniques of aortic valve reconstruction are evolving. Cardiac catheterization as a therapeutic intervention is routinely applied to stenotic mitral, aortic and pulmonary valves, and transcatheter replacement of an abnormal pulmonary valve is now a reality.

Cyanotic congenital heart disease the coronary arterial circulation.

BACKGROUND: The coronary circulation in cyanotic congenital heart disease (CCHD) includes the extramural coronary arteries, basal coronary blood flow, flow reserve, the coronary microcirculation, and coronary atherogenesis. METHODS: Coronary arteriograms were analyzed in 59 adults with CCHD. Dilated extramural coronaries were examined histologically in six patients. Basal coronary blood flow was determined with N-13 positron emission tomography in 14 patients and in 10 controls. Hyperemic flow was induced by intravenous dipyridamole pharmacologic stress. Immunostaining against SM alpha-actin permitted microcirculatory morphometric analysis. Non-fasting total cholesterols were retrieved in 279 patients divided into four groups: Group A---143 cyanotic unoperated, Group B---47 rendered acyanotic by reparative surgery, Group C---41 acyanotic unoperated, Group D---48 acyanotic before and after operation. RESULTS: Extramural coronary arteries were mildly or moderately dilated to ectatic in 49/59 angiograms. Histologic examination disclosed loss of medial smooth muscle, increased medial collagen, and duplication of internal elastic lamina. Basal coronary flow was appreciably increased. Hyperemic flow was comparable to controls. Remodeling of the microcirculation was based upon coronary arteriolar length, volume and surface densities. Coronary atherosclerosis was absent in both the arteriograms and the necropsy specimens. CONCLUSIONS: Extramural coronary arteries in CCHD dilate in response to endothelial vasodilator substances supplemented by mural attenuation caused by medial abnormalities. Basal coronary flow was appreciably increased, but hyperemic flow was normal. Remodeling of the microcirculation was responsible for preservation of flow reserve. The coronaries were atheroma-free because of the salutory effects of hypocholesterolemia, hypoxemia, upregulated nitric oxide, low platelet counts, and hyperbilirubinrmia.

The cardiac malpositions.

Dextrocardia was known in the 17th century and was 1 of the first congenital malformations of the heart to be recognized. Fifty years elapsed before Matthew Baillie published his account of complete transposition in a human of the thoracic and abdominal viscera to the opposite side from what is natural. In 1858, Thomas Peacock stated that "the heart may be congenitally misplaced in various ways, occupying either an unusual position within the thorax, or being situated external to that cavity." In 1915, Maude Abbott described ectopia cordis, and Richard Paltauf's remarkable illustrations distinguished the various types of dextrocardia. In 1928, the first useful classification of the cardiac malpositions was proposed, and in 1966, Elliott et al's radiologic classification set the stage for clinical recognition. The first section of this review deals with the 3 basic cardiac malpositions in the presence of bilateral asymmetry. The second section deals with cardiac malpositions in the presence of bilateral left-sidedness or right-sidedness. Previous publications on cardiac malpositions are replete with an arcane vocabulary that confounds rather than clarifies. Even if the terms themselves are understood, inherent complexity weighs against clarity. This review was designed as a guided tour of an unfamiliar subject.

The variant associations of aortic isthmic coarctation.

The term "coarctation" necessarily calls attention to a specific morphologic abnormality of the aortic isthmus. However, in this report, the author seeks to dispel the simplistic notion that coarctation is best characterized by isthmic obstruction, which is only 1 of an assemblage of abnormalities that include the proximal paracoarctation aorta, the distal paracoarctation aorta, the ascending aorta, the transverse aorta, the coronary arteries, the conduit arteries (radial, brachial, and carotid), the retinal vascular bed, dissecting aneurysms, cerebral aneurysms, vascular rings, systemic hypertension, and a decrease in left ventricular interpapillary muscle distance. Some of these abnormalities are secondary to the coarctation, such as collateral arteries and dissecting aneurysms. Others frequently or invariably coexist but are not secondary, such as bicuspid aortic valve and aneurysm of the circle of Willis. Still other abnormalities are seemingly contradictory, such as aneurysmal dilatation of the low-pressure distal paracoarctation aorta, while the high-pressure proximal segment does not dilate significantly. In conclusion, coarctation should be regarded as an assemblage of cardiovascular abnormalities rather than as isolated obstruction of the aortic isthmus.