Detrimental sequelae on the hemodynamics of the upper left limb after subclavian flap angioplasty in infancy

Vertebrobasilar insufficiency after subclavian flap aortoplasty for aortic coarctation

The mainstay of treatment of pediatric aortic coarctation is open surgery. One option for repair includes subclavian flap aortoplasty, first described by Waldhausen and Nahrwold in 1966. Within this technique, several modifications have been made over the years as long-term follow-up data became available. Early outcomes revealed little concern for left upper extremity limb ischemia or subclavian steal syndrome. These complications are rare but can have a significantly delayed presentation years after coarctation repair. We present a case of subclavian steal syndrome with lifestyle-limiting vertebrobasilar symptoms experienced by a patient 36 years after subclavian flap aortoplasty for aortic coarctation.

Left arm structure and function late after subclavian flap repair of aortic coarctation in childhood

OBJECTIVES

Concerns exist over the long-term consequences of subclavian artery ligation in subclavian flap repair for coarctation of the aorta. We sought to analyse upper limb structural and functional performance in adults who have had surgery in childhood for coarctation of the aorta, using either subclavian flap repair or end to end aortic anastomosis.

METHODS

Two-group observational design using anatomical and upper limb functional performance measures. Purposive sampling from our specialist adult congenital heart disease database of patients who received subclavian flap repair or end to end anastomosis for coarctation of the aorta as children. Upper limb measurements were completed using MRI and blood flow velocity with ultrasound imaging. Bilateral standardised upper limb functional testing of assessment of strength, dexterity and a standardised self-report of upper limb disability was completed.

RESULTS

Eighteen right-handed patients, 9 with subclavian repair, (38 ± 12 years, 78% males) were studied. Age at repair was 4.7 ± 5.9 years; mean time from initial repair 32 ± 9 years. The subclavian group had a larger difference between right and left when compared the end to end anastomosis group in: lower arm muscle mass (94.5 ± 42.3 mls versus 37.8 ± 94.5 mls, p = 0.008), lower arm maximal cross-sectional area, (5.9 ± 2.8 cm2 versus 2.9 ± 2.6 cm2, p = 0.038) and grip strength (14.7 ± 8.3 lbs versus 5.9 ± 5.3 lbs, p = 0.016) There were no significant functional differences between groups.

CONCLUSIONS

In adults with repaired coarctation of the aorta, those with subclavian flap repair had a greater right to left arm muscle mass and grip strength differential when compared to those with end to end anastomosis repair.

Symptomatic Subclavian Steal During Pregnancy in a Woman Status Post Coarctation Repair in Infancy

A 24-year-old woman with a history of coarctation repair by subclavian flap aortoplasty presented at 15 weeks' gestation with transient episodes of vision loss. She was diagnosed with subclavian steal syndrome and underwent left carotid artery to subclavian artery bypass at 17 weeks' gestation. She has had no recurrence of symptoms at ten months of postoperative follow-up. Despite the anatomic substrate for subclavian steal in patients with this type of surgical repair, neurologic symptoms are uncommon. It is possible that the pregnancy-induced fall in systemic vascular resistance triggered symptoms in this previously asymptomatic patient.

Coarctation of the aorta: Management from infancy to adulthood

Coarctation of the aorta is a relatively common form of congenital heart disease, with an estimated incidence of approximately 3 cases per 10000 births. Coarctation is a heterogeneous lesion which may present across all age ranges, with varying clinical symptoms, in isolation, or in association with other cardiac defects. The first surgical repair of aortic coarctation was described in 1944, and since that time, several other surgical techniques have been developed and modified. Additionally, transcatheter balloon angioplasty and endovascular stent placement offer less invasive approaches for the treatment of coarctation of the aorta for some patients. While overall morbidity and mortality rates are low for patients undergoing intervention for coarctation, both surgical and transcatheter interventions are not free from adverse outcomes. Therefore, patients must be followed closely over their lifetime for complications such as recoarctation, aortic aneurysm, persistent hypertension, and changes in any associated cardiac defects. Considerable effort has been expended investigating the utility and outcomes of various treatment approaches for aortic coarctation, which are heavily influenced by a patient’s anatomy, size, age, and clinical course. Here we review indications for intervention, describe and compare surgical and transcatheter techniques for management of coarctation, and explore the associated outcomes in both children and adults.

Coarctation of the aorta - the current state of surgical and transcatheter therapies

Aortic coarctation represents a distinct anatomic obstruction as blood moves from the ascending to the descending aorta and can present in a range of ages from infancy to adulthood. While it is often an isolated and discrete narrowing, it can also be seen in the more extreme scenario of severe arch hypoplasia as seen in the hypoplastic left heart syndrome or in conjunction with numerous other congenital heart defects. Since the first description of an anatomic surgical repair over sixty years ago, an evolution of both surgical and transcatheter therapies has occurred allowing clinicians to manage and treat this disease with excellent results and low morbidity and mortality. This review focuses on the current state of both transcatheter and surgical therapies, paying special attention to recent data on long-term follow-up of both approaches. Further, current thoughts will be explored about future therapeutic options that attempt to improve upon historical long-term outcomes.

Impaired arm development after Blalock-Taussig shunts in adults with repaired tetralogy of Fallot

BACKGROUND

Many adults with repaired tetralogy of Fallot have had prior Blalock-Taussig shunts. These shunts may theoretically hinder growth and development of the ipsilateral arm.

METHODS

We prospectively enrolled consecutive patients with tetralogy of Fallot in a cross-sectional study to measure arm length and assess handgrip strength. Bilateral handgrip strength was quantified by a dynamometer in a standing position after instructing patients to clench each hand tightly in succession. The maximum force achieved, in kilograms, was measured.

RESULTS

A total of 80 consecutive adults with tetralogy of Fallot, aged 36.0 ± 12.5 years, 49% female, were prospectively enrolled. Thirty-eight (47.5%) patients had prior Blalock-Taussig shunts at a median age of 1.0 year. Twenty-one (55.3%) were left-sided and 23 (60.5%) were classic shunts. All but six patients with right-sided shunts and one without a prior shunt were right-handed. The shunts were present for a median of 4.0 years prior to takedown during corrective surgery. The arm ipsilateral to the shunt was significantly shorter than the contralateral arm (71.5 ± 6.1 versus 73.6 ± 5.6 cm, P<0.0001). Handgrip strength was significantly weaker on the ipsilateral versus contralateral side (median [IQR], 26.5 [14.0-41.5] versus 31.0 [18.0-46.0] kg, P<0.0001) and the ipsilateral-to-contralateral handgrip ratio was lower with classic versus modified shunts (median [IQR], 1.05 [1.02-1.14] versus 1.19 [1.07-1.33] kg, P=0.0541).

CONCLUSION

In patients with tetralogy of Fallot, Blalock-Taussig shunts may impair normal development of the ipsilateral arm with repercussions in adulthood that include shorter limb length and reduced handgrip strength. These changes are most pronounced in patients with classic end-to-side anastomoses.

Long-Term Results of the Subclavian Flap Repair for Coarctation of the Aorta in Infants

Background:

Coarctation is a congenital narrowing of the aorta that often requires repair during infancy. The subclavian flap aortoplasty was once widely favored for its avoidance of a circumferential suture line and low incidence of recoarctation. The aim of this study is to report the long-term results of the subclavian flap repair for coarctation of the aorta in infants.

Methods:

Our operative database was queried for infants with coarctation who underwent subclavian flap aortoplasty from 1966 to 1991. Medical records were reviewed for patient characteristics and outcomes. Survivors were identified for additional phone interview.

Results:

Fifty-five patients met the inclusion criteria. There were 7 early deaths (in hospital), 11 late deaths, 5 patients lost to follow-up, and 32 known long-term survivors with a mean follow-up of 22.0 years (range 2.4-34.9). Hospital mortality was not associated with patient characteristics but was associated with earlier year of surgery ( P = .015). A trend toward decreased overall survival was seen in patients with coarctation with associated cardiac defects ( P = .072). Reintervention for recoarctation was required in 3 (6.6%) patients and was not related to the patient characteristics. There were no apparent complications related to subclavian artery sacrifice.

Conclusions:

Subclavian flap aortoplasty provides excellent long-term results for the repair of coarctation in infants. The incidence of recoarctation requiring reintervention is low and compares favorably with other techniques. Compromise of growth or function of the left arm was not appreciated. The subclavian flap technique remains a viable surgical option for the repair of coarctation in infants.

Subclavian flap aortoplasty and preservation of left upper extremity circulation using an interposition graft

OBJECTIVES

To introduce a surgical technique to maintain left upper limb blood flow after subclavian flap aortoplasty (SFA).

METHODS

Five patients (9 to 23 months of age) with a diagnosis of long-segment aortic coarctation underwent conventional SFA. A Gore-tex graft was interposed between the stump and the proximal descending aorta to maintain perfusion of subclavian artery.

RESULTS

All patients had a patent Gore-tex graft and normal blood flow of the subclavian artery and left upper limb. One patient expired and four others were discharged with a mean follow-up of 48 months. On follow-up all patients had normal development of the left upper limb and no signs of limb ischemia. Echo findings revealed normal arch flow with normal flow in the Gore-tex graft and left upper extremity.

CONCLUSIONS

Interposing a Gore-tex graft between the subclavian artery stump and proximal descending aorta concomitant with SFA can be safely performed in infants with long-segment aortic coarctation, with preservation of left upper extremity circulation.

Balloon angioplasty with stenting to correct a functionally interrupted aorta: A case report with three-year follow-up

A 16-year-old male presenting with upper extremity hypertension was found to have a severe form of discrete coarctation with complete luminal obliteration, causing a functional interruption of the thoracic aorta. Fluoroscopically guided perforation of the obstruction and creation of a neo-aortic lumen was performed. This was followed by balloon angioplasty and stent placement, successfully relieving the coarctation. The procedural method, acute and late follow-up results, and a discussion of the potential risks and benefits are presented.

Aortic coarctation: an overview

In severe aortic coarctation in the neonatal period, surgical repair is required soon after clinical stabilization. Elective repair of isolated aortic coarctation is nowadays indicated at 3-6 months of life or at the time of diagnosis. At present, no single operation appears to have a clear superiority. However, during the first months of life, an extended end-to-end anastomosis is considered the best option by most authors, even though weight at operation and anatomy of the aortic arch are also significant determinants of late recoarctation. In cases of aortic arch hypoplasia, which occurs in up to 70% of neonatal and infant coarctations, especially when associated anomalies are present, surgery seems the treatment of choice. After 3 months of age and in the adult population, balloon angioplasty and stent placement are considered a suitable option. Recently, we adopted a median sternotomy approach without the use of extracorporeal circulation for the treatment of aortic coarctation with a hypoplastic aortic arch. We treated 11 patients with satisfactory results at an average follow-up of 40 months.

Is extended arch aortoplasty the operation of choice for infant aortic coarctation? Results of 15 years' experience in 181 patients

BACKGROUND

Recurrent coarctation is an ever-present complication of surgical treatment of coarctation of aorta (CoA) among infants. No single operation appears to have a clear superiority.

METHODS

From January 1, 1986, to June 30, 2002, a consecutive series of 181 patients less than 1 year of age (range 1 to 300 days, median 13.5 days) were referred for CoA repair. Neonates accounted for 135 patients, and hypoplastic arch (less than 1 mm/kg plus 1) was present in 107 infants. Coarctation of aorta was simple (group 1) in 71 patients; complicated by ventricular septal defect (group 2) in 62; and complicated by complex congenital heart disease (group 3) in 48. All patients were assessed by right arm/left leg Dynamap pressures and routine follow-up was performed by the cardiologists. Follow-up was complete in all patients (range 6 months to 16 years, median 7.5 years).

RESULTS

The overall hospital/30-day mortality was 0.5% (group 1 = 0, group 2 = 0, group 3 = 1 [2.0%]). Complications other than recoarctation occurred in 5 patients (2.7%). Late mortality occurred in 15 (11 at intracardiac repair). Recoarctation, ie, a gradient of more than 20 mm Hg, occurred in 4 patients (2.2%). All 4 patients were noted to have a gradient of more than 10 mm Hg (right arm/left leg) postoperatively and as such had residual coarctation. All 4 were successfully treated by balloon aortoplasty.

CONCLUSIONS

Extended arch aortoplasty in association with ductal and coarctation excision provides excellent coarctation repair with a low incidence of recoarctation. Recoarctation occurred only in proximal aortic arch hypoplasia or low birth weight. Balloon aortoplasty easily and effectively relieved the recoarctation in all cases.

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

Upper limb ischemia after subclavian flap aortoplasty: unusual long-term complication

Repair of isolated coarctation of the aorta by subclavian flap aortoplasty carries the disadvantage of impaired blood supply to the left arm. However, ligation of branches of the subclavian artery can be tolerated without manifest ischemia of the upper extremity. We report the case of a young man who suffered from left upper extremity ischemia 18 years after initial operation. Treatment consisted of carotid-subclavian bypass with good outcome. The surgical approach of coarctation by subclavian aortoplasty should be reserved for specific cases, and if this procedure is performed, ligation of branches of the subclavian artery should be minimized to increase inflow into the left brachial artery.

Arm ischemia after subclavian flap angioplasty: repair by carotid-subclavian bypass

Though quite unusual, vascular insufficiency of the arm can occur after ligation of the subclavian artery. We describe the ischemic consequences of left subclavian interruption in a neonate after subclavian flap angioplasty repair (Waldhausen procedure) for coarctation. Subsequent carotid-subclavian artery bypass was successful in relieving symptoms.

Resection of atherosclerotic aneurysm at origin of aberrant right subclavian artery

In two patients (75- and 88-years-old), with the aid of cardiopulmonary bypass and using a transaortic approach, a rare calcified aneurysm at the origin of an aberrant right subclavian artery was closed with a prosthetic patch. The aneurysm was partially resected and the remainder closed over the patch. This technique obviates the need for hazardous clamping of the aorta around the base of the calcified aneurysm and allows secure closure of the origin of the aneurysm.

Repair of coarctation with resection and extended end-to-end anastomosis

BACKGROUND

Our surgical strategy for infant coarctation changed from subclavian flap aortoplasty to resection with extended end-to-end anastomosis in 1991. The purpose of this review was to evaluate the results of that strategy.

METHODS

From 1991 through 1997, 55 infants underwent repair of coarctation of the aorta using resection with extended end-to-end anastomosis. Isolated coarctation of the aorta was present in 26 patients, 20 patients had a ventricular septal defect, and 9 patients had other associated intracardiac lesions. Mean age at surgery was 0.20+/-0.24 years (median, 21 days). In 34 patients (62%), arch reconstruction was performed through a left thoracotomy. Twenty patients (36%) had median sternotomy with simultaneous repair of coarctation of the aorta and intracardiac repair of associated lesions. One patient had recoarctation repair through a median sternotomy. All coarctation and ductal tissue was resected and the anastomosis was constructed starting opposite the left carotid artery with running polypropylene suture.

RESULTS

There was one early death 26 days after coarctation of the aorta and ventricular septal defect repair in a child on extracorporeal membrane oxygenation for meconium aspiration and 2 late deaths owing to pneumonia and pulmonary hypertension (1) and interventricular hemorrhage (1). There were no instances of paraplegia. Follow-up in survivors ranges from 10 to 76 months (mean, 39.8+/-17.2 months). Recoarctation has developed in 2 patients, who have had successful balloon dilation 6 and 14 months after the operation. This yields a low recoarctation rate of 3.6%.

CONCLUSIONS

Resection with extended end-to-end anastomosis yields a low mortality and particularly a low recoarctation rate and is our procedure of choice for infants with coarctation of the aorta.

Surgical controversies: coarctation

Fifty one years have passed since grossand Crafoord independently reported successful repair of aortic coarctation. One could be forgiven for assuming that all the surgical controversies have now been settled. This is far from the case, as the numerous publications (frequently with opposing view points) related to timing, technique and complications bear testament. Perhaps the passage of the golden anniversary of this operation should stimulate a degree of reflection among surgeons and cardiologists.

Repair of coarctation of the aorta in neonates and young infants

In repair of coarctation in neonates or young infants, inadequate removal of ductal tissue, failure to address hypoplasia of the aortic arch, and suture line tension have been reported to be important factors of residual or early recurrent stenosis at the coarctation repair site. In a consecutive series of neonates and young infants with coarctation, who were all operated without delay with extended resection, the clinical outcome regarding the development of restenosis and hypertension was studied. In addition, the resected specimens were investigated regarding the completeness of resection of ductal tissue. Twenty-five consecutive neonates and young infants (median age 22 days, range 5 to 39 days) who underwent surgical correction of coarctation were reviewed; the resected specimens were examined histologically to document the extent of ductal tissue in the aortic wall. Fifteen patients had a preductal coarctation with associated cardiovascular anomalies including a hypoplastic aortic arch (n = 11). The remaining 10 patients had a paraductal coarctation without associated intracardiac anomalies. In all patients, the isthmus was bypassed and an end-to-side anastomosis was constructed between the descending aorta and the undersurface of the proximal aortic arch (n = 13) or the distal ascending aorta (n = 12). In 13 patients without marked hypoplasia of the aortic arch, the coarctation repair was performed through a left thoracotomy. In the remaining 12 patients, the coarctation was repaired through a median sternotomy with CPB and hypothermic circulatory arrest, on the basis of an associated hypoplastic aortic arch (n = 4), hypoplastic aortic arch with intracardiac anomalies (n = 7), or a "bovine" innominate artery (n = 1). There was no perioperative or late mortality. At a median follow-up of 15 months, 1 patient (4%) developed a recurrent stenosis at the coarctation repair site; in the remaining 24 patients, echocardiography showed a widely patent anastomosis with no evidence of a hemodynamically significant gradient. None of the patients had hypertension. Histologic examination of the resected specimens demonstrated the presence of ductal tissue in the descending aorta with maximal extension into its lateral wall (mean 5.2 mm). In all specimens of the paraductal subtype, there was also extension of ductal tissue into the lateral wall of tbe isthmus (mean 3.9 mm). We conclude that: (1) in the absence of marked hypoplasia of the proximal aortic arch, coarctation can be repaired with low mortality and morbidity via a left thoracotomy; (2) in the presence of marked hypoplasia of the proximal aortic arch and/or if associated intracardiac defects also need to be repaired, we advocate repair of the coarctation and associated defects through a median sternotomy with circulatory arrest; (3) in view of the absence of postoperative hypertension in this series, early repair of aortic coarctation is recommended; and (4) because ductal tissue may extend not only into the descending aorta but also into the isthmus, complete excision of the coarctation and bypass of the isthmus are valuable techniques to avoid secondary constriction of the aorta by ductal tissue.

Coarctation repair using end-to-side anastomosis of descending aorta to proximal aortic arch

BACKGROUND

Recurrent aortic coarctation after primary operative repair in the neonate and small infant is seen most commonly within the first year of life. Inadequate removal of ductal tissue, failure to address hypoplasia of the aortic arch, and suture line tension have been cited as important factors in early recurrence.

METHODS

To address these issues, we have used a technique of coarctation resection and extended anastomosis of the descending aorta to the undersurface of the aortic arch. THe salient features of this approach include extensive mobilization of the aortic arch and neck vessels, careful trimming of all ductal tissue, ligation of the isthmus just beyond the left subclavian artery, and end-to-side anastomosis of the descending aorta to a separate incision in the undersurface of the aortic arch proximal to all tubular hypoplasia. Between July 1992 and January 1995, 19 consecutive neonates (median age, 13 days) and 4 consecutive infants under 3 months of age (median age, 69 days) with a mean peak systolic upper to lower extremity resting gradient of 27.9 +/- 16.9 mm Hg underwent repair of aortic coarctation and tubular hypoplasia of the arch. Other procedures performed at the time of repair included ligation of a patent ductus arteriosus (n = 19), pulmonary artery banding (n = 3), and closure of ventricular septal or atrial septal defect (n = 3).

RESULTS

There were no perioperative deaths. Early postoperative complication included a recurrent laryngeal nerve injury and a transient focal tonic clonic seizure. There was one late death, after a subsequent intracardiac surgical procedure, at a median follow-up of 16 months (range, 1 to 29 months). Twenty-one of 22 late survivors were free of recurrent aortic coarctation by echocardiography findings and clinical examination, with a median upper to lower extremity gradient of 0 mm Hg. Reintervention for recurrent aortic coarctation was not required in any survivor.

CONCLUSIONS

The technique described herein completely removes all potentially abnormal tissue from the aorta, including ductal tissue and all tubular hypoplastic tissue proximal to the coarctation site.

Surgical management of neonatal coarctation

Between 1983 and 1994, 307 consecutive neonates underwent coarctation repair by a single surgical technique: extended end-to-end anastomosis. Mean age at operation was 13 +/- 8 days. Isolated coarctation was present in 95 patients (group 1), 102 patients had associated ventricular septal defect (group 2), and 110 patients had associated complex intracardiac lesions (group 3). Aortic arch hypoplasia was present in 81% of the patients (62% in group 1 versus 85% in group 2 and 93% in group 3: p < 0.001). In 271 patients, the aortic arch reconstruction was performed via a left thoracotomy with normothermia (100% of group 1, 95% of group 2, and 72% of group 3); in the other 36 patients, undergoing one-stage repair or palliation of the associated lesion, it was performed via a midline sternotomy during a short period of deep hypothermia and circulatory arrest (5% of group 2 and 28% of group 3). Pulmonary artery banding was performed in 94 patients. Spontaneous ventricular septal defect closure was observed in 39% of the patients of group 2 operated on via thoracotomy. Early mortality rates in groups 1 (2%) and 2 (2%) were significantly lower than in group 3 (17%) (p < 0.001). There were 29 late deaths, all related to associated cardiac lesions or their subsequent repair. The overall total mortality was 16.9%. In group 3 this rate was significantly higher in patients undergoing two-stage procedures (47%) than in those undergoing one-stage repair (23%) (p < 0.05). All but 14 survivors were followed up for a mean of 61 +/- 36 months. Actuarial survivals at 10 years were 98% in group 1, 94% in group 2, and 60% in group 3. The recoarctation rate was 9.8%, leading to 21 reoperations and three angioplasties without mortality. Patients with a more extended or severe form of aortic arch hypoplasia had a significantly higher risk of recoarctation (p < 0.001). Actuarial freedom from reoperation for recoarctation at 10 years was 93%. The findings of this study suggest that extended end-to-end anastomosis provides an adequate and safe repair of neonatal coarctation. Low recoarctation rate, owing to effective relief of the obstruction created by aortic arch hypoplasia and to complete resection of ductal tissue, freedom from major morbidity, and feasibility via both lateral and anterior approaches are the main advantages of the extended end-to-end anastomosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Systemic-pulmonary shunt with a right retroesophageal subclavian artery

A 19-day-old child suffering from cyanosis due to tetralogy of Fallot was palliated by using his right retroesophageal subclavian artery. It was anastomosed side-to-side onto the ascending aorta and end-to-side onto the right pulmonary artery. The palliation obtained with this systemic-pulmonary shunt was satisfying. The right brachial vascular flow was normal.

Surgical treatment of vascular rings: the Mayo Clinic experience

From 1947 through 1992, 37 Mayo Clinic patients underwent operation for the relief of tracheoesophageal obstruction that resulted from vascular rings and related entities. Of the 37 patients, 18 had a double aortic arch, 11 had a right aortic arch with an aberrant left subclavian artery, 4 had a left aortic arch with an aberrant right subclavian artery, 2 had a pulmonary artery sling, 1 had a right aortic arch with mirror-image branching and a left ligamentum arteriosum, and 1 had a left aortic arch, a right descending aorta, and a right ductus arteriosus. Symptoms consisted of stridor, recurrent respiratory infections, and dysphagia. The anomaly was approached through a left thoracotomy in 31 patients, through a right thoracotomy in 4, and through a median sternotomy in 2. Only one early postoperative death (3%) and no late deaths occurred. At long-term follow-up (maximal duration, 45 years), three patients had residual symptomatic tracheomalacia, one of whom required right middle and lower lobectomy for recurrent pneumonia. Magnetic resonance imaging is the imaging technique of choice for accurate delineation of the vascular and tracheal anatomy. When patients are symptomatic, vascular ring should be repaired. The surgical risk is minimal, and the long-term results are excellent.

Noninvasive hemodynamic assessment of the internal mammary artery in myocardial revascularization

Using transthoracic B-mode imaging and Doppler spectrum analysis it was found that the luminal diameter of the internal mammary artery and its hemodynamics were not significantly different among 15 preoperative patients (64 +/- 10 years) who underwent myocardial revascularization using the left internal mammary artery and young and older control groups (25 +/- 3 years and 61 +/- 9 years, respectively). These data indicate that older age does not significantly adversely influence the degree of intimal thickening and compliance in the internal mammary artery. Doppler spectrum analysis of the internal mammary artery in the patients who were operated on revealed conversion from a triphasic systolic waveform preoperatively to a unidirectional combined systolic/diastolic waveform at 1 week and 2 and 6 months postoperatively, characterized by a significant increase in the diastolic blood flow velocity and a significant decrease in the systolic blood flow velocity and the pulsatility and resistance indices. This study indicates that transthoracic B-mode imaging and Doppler spectrum analysis are promising noninvasive techniques in the preoperative assessment of internal mammary artery morphology and physiology. In addition, Doppler spectrum analysis can also be used in the long-term serial assessment of the internal mammary artery conduit after myocardial revascularization.

Reactive hyperemia in the nonused internal mammary artery after median sternotomy

Doppler spectrum analysis was performed in the nonused internal mammary artery in a group of patients who underwent myocardial revascularization using the contralateral internal mammary artery and in both internal mammary arteries in a group of patients who underwent median sternotomy for cardiac surgical procedures in which the internal mammary artery was not used. In all nonused internal mammary arteries the preoperatively triphasic systolic flow pattern had postoperatively converted into a unidirectional systolic flow pattern with a large diastolic flow component, characterized by a significant increase in the diastolic flow parameters and a significant decrease in the resistance and pulsatility indices. This effect had almost subsided at 6 months postoperatively. This study indicates that the reactive hyperemia observed in the nonused internal mammary artery in the early postoperative period is mainly caused by the temporarily increased metabolic demand of the anterior thoracic wall and mediastinum, rather than by the metabolic demand of the anterior diaphragm and the contralateral rectus abdominis muscle after deprivation of their main nutritional vessel.