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Derek A Fyfe

Publications and source records attributed to Derek A Fyfe.

13 recordsLinked to original sources
PubMed2006

Reduction in initial ventricular systolic and diastolic velocities after heart transplantation in children: improvement over time identified by tissue Doppler imaging.

BACKGROUND: Tissue Doppler imaging (TDI) is a non-invasive method for measuring ventricular function that can provide insight into the changes in hemodynamics that occur after pediatric heart transplantation. The purpose of this study was to quantify longitudinal changes in myocardial velocities within the first 6 months after transplantation in children. METHODS: Thirteen patients were serially studied (median age at transplant 5.9 years) and compared with controls. Tissue Doppler systolic (S), early (E) and late (A) diastolic velocities were recorded at the tricuspid annulus, mitral annulus and interventricular septum. RESULTS: TDI studies were serially performed during 6 months post-transplantation: <10 days (n = 48); 11 to 30 days (n = 26); 31 to 60 days (n = 13); 61 to 120 days (n = 12); and 121 to 180 days (n = 16). Mean systolic tissue velocities at the tricuspid annulus were 3.8 cm/s (95% confidence interval [CI]: 3.1 to 4.6) at baseline (<10 days) and 6.3 cm/s (95% CI: 4.1 to 8.6) at 6 months post-transplantation (mean increase from baseline: 2.5 cm/s; 95% CI: 0.1 to 4.9). Systolic tissue velocities at the mitral annulus also increased over time (mean change from baseline: 0.9 cm/s; p = 0.02). Early diastolic (E) velocities at the tricuspid annulus and mitral annulus significantly improved over time (p < 0.0001 and p = 0.002, respectively). Systolic and diastolic velocities measured at >121 days after transplantation, however, remained significantly lower than those of normal controls. CONCLUSIONS: TDI demonstrated systolic and diastolic velocities improved during the initial 180 days after heart transplantation. Systolic and diastolic velocities were reduced in children after heart transplantation when compared with controls.

Adolescent↗
PubMed2006

Velocity-encoded magnetic resonance image assessment of regional aortic flow in coarctation patients.

BACKGROUND: During primary coarctation repair, collateral blood vessels contribute significantly to distal perfusion. We sought to determine if velocity-encoded cine magnetic resonance imaging (VENC-MRI) could provide insight into anatomy and hemodynamics of collateral flow in patients with unrepaired coarctation. METHODS: Sixteen patients (median age, 6.2 years; range, 1 to 18) with discrete coarctation (65% severe, 29% mild-moderate) and 10 controls (median age, 12.0 years; range, 9 to 15) without left-sided heart lesions were referred for cardiac MRI. Flow volumes were calculated from VENC-MRI images at the coarctation (proximal), diaphragm (distal), and midway between the two points (midpoint). A means model, repeated-measure analysis, was performed for volumes. RESULTS: In coarctation patients, flow volumes increased by 59% (p = 0.0002) from coarctation to diaphragm, primarily between the proximal and midpoint sites (by 77%, p < 0.0001). In controls, flow volumes decreased by 11% along the entire aortic study length. Coarctation volumes were lower than controls by 54% (p = 0.0003) at the proximal site but showed no statistical difference at the midpoint or diaphragm. CONCLUSIONS: Coarctation flow volumes maximally increase in the upper thoracic aorta, but approach normal flow volumes in the lower thoracic region. Arteries arising from mid and lower thoracic level, such as those supplying the anterior spinal cord, may have nearly normal flow if collaterals are present. Velocity-encoded MRI can evaluate flow in patients who have poor collateral circulation to improve surgical planning and decrease neurologic complications of coarctation repair.

Adolescent↗
PubMed2006

Elastic properties of the reconstructed aorta in hypoplastic left heart syndrome.

BACKGROUND: Patients with repaired coarctation of the aorta retain abnormal elastic properties of the aorta. It is not known whether patients with hypoplastic left heart syndrome also manifest abnormal elastic properties after palliative surgery. The presence of such abnormalities may have important clinical implications as reduced aortic compliance might adversely impact single right ventricular function. METHODS: We prospectively evaluated the elastic properties of the aorta in a cohort of patients with hypoplastic left heart syndrome who had undergone the Norwood procedure with aortic arch reconstruction and subsequent bidirectional Glenn or Fontan procedure. The hypoplastic left heart syndrome patients (n = 20) were compared with single-ventricle patients (n = 18) without history of arch reconstruction and patients with double-ventricular lesions (n = 22). Aortic elastic function was quantified by distensibility index and stiffness index. M-mode measurements of the transverse aortic arch were obtained with transesophageal echocardiography under general anesthesia. Patients were evaluated at a median age of 22.2 months with no age difference between patient subgroups. RESULTS: Distensibility index was significantly less (p = 0.007) and stiffness index greater (p = 0.005) in the reconstructed arch of hypoplastic left heart syndrome patients compared with single-ventricle and double-ventricle patients. CONCLUSIONS: Patients with hypoplastic left heart syndrome after Norwood palliation have increased aortic stiffness and decreased distensibility in the reconstructed transverse arch. As previous studies in adults have shown that decreased aortic compliance increases the energy cost of cardiac ejection, examination of modifications to the surgical technique that might improve elastic properties is warranted.

Aorta, Thoracic↗
PubMed2006

Tissue Doppler imaging detects severely abnormal myocardial velocities that identify children with pre-terminal cardiac graft failure after heart transplantation.

BACKGROUND: Children with orthotopic heart transplants (OHT) may die or require retransplantation due to chronic graft failure usually due to severe coronary allograft vasculopathy (CAV). Non-invasive detection of chronic transplant failure has been problematic due to lack of specific echocardiographic findings. Tissue Doppler Imaging (TDI) is a non-invasive ultrasound methodology, which measures myocardial contraction and relaxation velocities. The purposes of this study were to: 1. Determine quantitative changes of longitudinal TDI velocities characteristic to "pre-terminal" patients who subsequently either died or were listed for re-transplantation due to graft failure; 2. to define the time course of these changes, and 3. to show whether RV and LV velocities were equally effected. METHODS: 53 heart transplantation recipients were evaluated. Of these, 45 were "well" patients. They ranged in age at enrollment from 0.5 to 20.1 (mean 10.21) years, age at transplantation from 0.2 to 18 (mean 5.7) years. The time from transplantation to enrollment was 1 day to 14.9 (mean 4.5) years. There were 8 "pre-terminal" (test group) patients who died or were listed for re-transplantation within 9 months after TDI echo. These ranged in age from 2.6 to 17 (mean 11.6) years, age at transplant from 1 month to 15.9 (mean 8.1) years, and time from transplant to enrollment was 0.7 to 9.8 (mean 3.6) years. TDI was performed in the apical four-chamber view. Systolic (S, cm/s) and diastolic early (E, cm/s) and late (A, cm/s) velocity. Mitral and tricuspid annular TDI velocities were measured. Tricuspid regurgitation and LV ejection fraction were also compared. RESULTS: Pre-terminal patient's Left Ventricular Ejection Fraction began diverging from controls at 3 to 6 months prior to endpoint (p < 0.001). Tricuspid TDI S velocities of pre-terminal patients diverged by 2.0 cm/sec from controls (p < 0.002) 6 months prior to, and reduced further by 2.9 cm/sec 3 months prior to endpoint (p < 0.001). Tricuspid TDI E velocities diverged 3 to 6 months before endpoint, by 1.9 cm/sec (p < 0.02) and by 3.7 cm/sec 0-3 months prior to endpoint, (p < 0.001). Mitral S velocities diverged from controls by 1.5 cm/sec at 0 to 3 months before terminal endpoints (p = 0.002). Mitral E velocities were statistically similar at all time intervals (p > or = 0.15). Septal S velocities equaled controls 6 months (p = 0.92) and between 3 to 6 months (p = 0.83) but diverged by 1.6 cm/sec 0 to 3 months before terminal endpoints (p = 0.01). Septal E velocities equaled controls. Mortality Prediction: LVEF, tricuspid annulus systolic and diastolic velocities, and tricuspid regurgitation severity were significant in predicting mortality. Coronary angiography was performed in 26 patients, 5 had severe coronary artery disease and all were pre-terminal. DISCUSSION: The TDI data reported here show 3 to 6 months before the terminal graft failure, tricuspid, but not mitral, S and E TDI velocities, deteriorated to uniquely low levels not seen in other clinically well pediatric transplant recipients. Further RV deterioration occurred during the final 3 months before death and severely reduced left ventricular velocities then occurred. Small decreases in LVEF and progressive increases in the severity of tricuspid regurgitation were also detectable and predicted an increased likelihood of mortality. Seven of the 8 preterminal patients had angiograms 5 of which showed severe CAV. These data suggest that there is a critical "pre-terminal" window of time in which children demonstrate uniquely reduced right and subsequently left sided myocardial velocities at approximately 6 months prior to graft failure. The practice of annual catheterization and coronary angiography may not allow caregivers an opportunity to intervene early in the process of graft dysfunction. Therefore, a strategy of tissue Doppler echocardiography 2 or 3 times each year might be an appropriate regimen to survey for graft impairment.

Adolescent↗
PubMed2006

Left ventricular aneurysm in a five-week-old child.

Ventricular aneurysms in the pediatric population are rare and no standardized method of treatment exists. We present a case of left ventricular (LV) aneurysm in an infant, 5 weeks after a balloon aortic valvuloplasty for congenital aortic stenosis.

Aortic Valve Stenosis↗
PubMed2004

De Vega tricuspid annuloplasty for systemic tricuspid regurgitation in children with univentricular physiology.

BACKGROUND AND AIM OF THE STUDY: Significant tricuspid valve regurgitation (TR) is problematic in children with univentricular physiology and a systemic tricuspid valve occasionally requiring tricuspid (systemic atrioventricular) valve replacement. Since 1998, the De Vega tricuspid annuloplasty technique has been applied for TR in these children. METHODS: Twelve children (median age 2.2 years; range: 6 months to 17 years) with moderate or severe systemic TR underwent a De Vega tricuspid annuloplasty during a bidirectional Glenn anastomosis (n = 3), Fontan procedure (n = 8) or aortic valve replacement late after a Fontan procedure (n = 1). Nine patients (75%) had prior Norwood palliation for hypoplastic left heart syndrome. Four patients had simultaneous repair of an abnormal tricuspid valve in addition to the De Vega procedure. RESULTS: There were no deaths during a mean follow up of 2.0 +/- 1.4 years (range: 6 months to 5.1 years). One child required pacemaker implantation early after operation, and one child with a Glenn anastomosis underwent cardiac transplantation 21 months postoperatively. In the remaining 11 patients, the most recent echocardiogram showed mild or no TR in eight children, mild-to-moderate TR in one child, and moderate TR in two children. No child had symptomatic TR (including the two with moderate TR), significant tricuspid stenosis, or late pacemaker implantation. CONCLUSION: The De Vega tricuspid annuloplasty safely provides excellent relief of systemic TR in children with univentricular physiology, with a majority of patients (73%) having mild or less residual TR at follow up examination. This simple technique is preferred to tricuspid (systemic) valve replacement in these children.

Adolescent↗
PubMed2003

Tricuspid regurgitation in patients with repaired Tetralogy of Fallot and its relation to right ventricular dilatation.

In a cohort of 56 school-aged children with repaired tetralogy of Fallot, significant (moderate to severe) tricuspid regurgitation was common (32% of patients) and was related to both tricuspid annulus dilatation and structural valve abnormalities that were potentially related to previous surgery. Even after adjusting for pulmonary regurgitation, tricuspid regurgitation was significantly correlated with right ventricular volume (r= 0.39, p = 0.009), suggesting that tricuspid regurgitation as well as pulmonary regurgitation may contribute significantly to progressive right ventricular dilatation in this population.

Cardiac Volume↗
PubMed2003

Results with the freestyle porcine aortic root for right ventricular outflow tract reconstruction in children.

BACKGROUND: The ideal choice for valved reconstruction of the right ventricular outflow tract (RVOT) in children is undetermined. This study explores the Freestyle porcine aortic root for these patients. METHODS: From January 1998 to December 2002, 56 patients ages 1.6 to 29.9 years old (mean 11.8 years old) underwent RVOT reconstruction using a Freestyle porcine aortic root. The patients averaged 1.9 prior operations (range 0 to 5) for tetralogy of Fallot +/- pulmonary atresia (28 patients), critical pulmonary stenosis (10 patients), Ross procedure (5 patients), pulmonary atresia/intact ventricular septum (4 patients), complete atrioventricular septal defect +/- tetralogy of Fallot (4 patients), and others (5 patients). At time of RVOT reconstruction, 42 patients (75%) had additional procedures including the following: tricuspid or mitral repair (24 patients), pulmonary arterioplasty +/- Glenn (12 patients), ventricular septal defect closure (5 patients), aortic valve replacement (3 patients), placement of a cardioverter/defibrillator or pacemaker (3 patients), and others (8 patients). RESULTS: One patient developed mediastinitis; another was treated for Candida endocarditis (his excised homograft unexpectedly grew Candida). All patients are well on follow-up from 2 to 60 months (mean 30 +/- 20 months) with no deaths. The patient with endocarditis underwent conduit replacement for recurrent pulmonary stenosis 3.5 years postoperatively. Echocardiography revealed mild or no pulmonary insufficiency in 93%. The calculated mean peak systolic RVOT gradient by echocardiography was 19.7 +/- 15.4 mm Hg. CONCLUSIONS: These data demonstrate excellent results with the Freestyle bioprosthesis for RVOT reconstruction in children. This valve may serve as a readily available alternative to homograft valves in RVOT reconstruction, particularly since early insufficiency seems to be less problematic. Questions of long-term durability and significance of echocardiographic stenosis remain unanswered.

Adolescent↗
PubMed2003

Reduction of tricuspid annular doppler tissue velocities in pediatric heart transplant patients.

BACKGROUND: Orthotopic heart transplantation is a life-saving therapy for children with end-stage heart disease. However, 50% of these transplanted children die or require re-transplantation 12 years later. Progressive deterioration of cardiac function is a common feature of long-term survivors; however, quantitative evaluation of the state of the right ventricle has been lacking. Tissue Doppler imaging (TDI) has been used to measure alterations in right ventricular (RV) function in other illnesses. The purpose of this study was to quantitate abnormalities in tricuspid annular systolic and diastolic velocities as an indicator of RV dysfunction, and to evaluate if time since transplantation and the presence of tricuspid regurgitation are associated with quantitative changes in tricuspid annular velocities in pediatric heart transplant recipients. METHODS: TDI was performed and velocities recorded during systole and early and late diastole at the tricuspid annulus, septum and mitral annulus in transplanted patients and in a control group with normal hearts. Pulsed wave Doppler mitral and tricuspid inflows were also measured and the severity of tricuspid regurgitation was estimated using color flow mapping. Patients with biopsy evidence of active cellular rejection or left ventricular ejection fraction of <60% were excluded from study. RESULTS: Thirty-five patients were divided into a normal heart group (n = 14) and a transplant group (n = 21), aged from 1 to 23 years. Systolic and early diastolic velocities at the tricuspid annulus and septum in the transplant group were reduced significantly compared with the normal group (p < 0.05): tricuspid annular systolic, 5.8 +/- 1.4 vs 9.4 +/- 1.7 cm/sec; early diastolic, -6.4 +/- 2.6 vs -9.7 +/- 2.6 cm/sec; septum systolic, 3.9 +/- 1.5 vs 5.8 +/- 1.4 cm/sec; and early diastolic, -6.3 +/- 2.4 vs -9.1 +/- 2.5 cm/sec. Patients were divided into early (<5 years) and late (>5 years) term groups since transplantation. Tissue velocities at the tricuspid annulus in the late term group had further reduction in systole, 4.9 +/- 1.4 vs 6.4 +/- 1.1 cm/sec, and early diastole, -5.3 +/- 1.5 vs -7.1 +/- 2.9 cm/sec (p < 0.05). Patients with severe tricuspid regurgitation had systolic and early diastolic velocities at the tricuspid annulus that were further reduced. Left ventricular mitral inflow Doppler early/late diastolic ratios became significantly different from the normal group 5 years after transplantation (p < 0.05). CONCLUSIONS: TDI demonstrated that tricuspid annular systolic and early diastolic velocities were abnormal in children after transplantation and became significantly more abnormal with prolonged time after transplantation. These alterations were not dependent on the presence of severe tricuspid regurgitation but appeared to be exacerbated by its presence. Evidence of diastolic left ventricular dysfunction was not detected before 5 years after transplantation in this unselected group. A prospective study may be required to define the evolution and progression of right and left ventricular dysfunction in children after heart transplantation.

Adolescent↗
PubMed2002

One hundred pulmonary valve replacements in children after relief of right ventricular outflow tract obstruction.

BACKGROUND: Surgical repair of obstructive lesions of the right ventricular outflow tract (RVOT) in children commonly creates pulmonary valve incompetence that may eventually require pulmonary valve replacement (PVR). We reviewed our experience with PVR late after RVOT reconstruction. METHODS: We performed 100 PVRs in 93 children 1.1 months to 22.4 years (median 8) after RVOT reconstruction. Children with right ventricular to pulmonary artery conduits and primary PVRs were excluded. Age at PVR was 4.5 months to 27.9 years (median 9.5 years). Initial diagnosis was tetralogy of Fallot and variants, 62; critical pulmonary stenosis, 15; pulmonary atresia with intact ventricular septum, 7; and others, 9. Eleven patients had a redo PVR. A total of 62 PVRs were homografts; 38 were porcine valves. RESULTS: There was one early death. On follow-up of 5 months to 12.4 years (mean 4.9 years) there were no late deaths although 1 child underwent cardiac transplantation. Actuarial freedom from redo PVR at 8 years was 100% for porcine valves but 70% for homograft valves (p = 0.17). For children younger than 3 years at PVR, freedom from reoperation was 76% at 1 year and 39% at 8 years compared with freedom from redo PVR at 8 years of 100% for children older than 3 years. On latest echocardiogram 97% of porcine valves had mild or no pulmonary regurgitation compared with 72% of homograft valves. CONCLUSIONS: PVR after RVOT reconstruction can be performed with low risk. Porcine valves may be superior to homograft valves although this advantage may be due to older age at time of PVR.

Adolescent↗