Coronary artery assessment in Kawasaki disease with dual-source CT angiography to uncover vascular pathology.

BACKGROUND: Kawasaki disease (KD) is a vasculitis with formation of coronary artery aneurysms (CAAs) that can lead to myocardial ischemia. Echocardiography is the primary imaging modality for the coronary arteries despite limited visualization. Coronary angiography (CAG) is the gold standard yet invasive with high-radiation exposure. To date however, state-of-the-art CT scanners enable high-quality low-dose coronary computed tomographic angiography (cCTA) imaging. The aim of our study in KD is to report (i) the diagnostic yield of cCTA compared to echocardiography, and (ii) the radiation dose. METHODS AND RESULTS: We collected data of KD patients who underwent cCTA. cCTA findings were compared with echocardiography results. In 70 KD patients (median age 15.1 years [0.5-59.5 years]; 78% male; 38% giant CAA), the cCTA identified 61 CAAs, of which 34 (56%, with a Z score > 3, in 22 patients) were not detected by echocardiography. In addition, the left circumflex (aneurysmatic in 6 patients) was always visible upon cCTA and not detected upon echocardiography. Calcifications, plaques, and/or thrombi were visualized by cCTA in 25 coronary arteries (15 patients). Calcifications were seen as early as 2.7 years after onset of disease. In 5 patients, the cCTA findings resulted in an immediate change of treatment. The median effective dose (ED) in millisievert differed significantly (p < 0.01) between third-generation dual-source and other CT scanners (1.5 [0.3-9.4] (n = 56) vs 3.8 [1.7-20.0] (n = 14)). CONCLUSIONS: The diagnostic yield of third-generation dual-source cCTA combined with reduced radiation exposure makes cCTA a favorable diagnostic modality to complete the diagnosis and long-term treatment indications for KD. KEY POINTS: • cCTA is a favorable diagnostic modality to complete the diagnosis and long-term treatment indications for Kawasaki disease. • Kawasaki disease patients with proven coronary artery involvement on echocardiography require additional imaging.

Transition from paediatric to adult care of adolescent patients with congenital heart disease: a pathway to optimal care.

INTRODUCTION: Adolescents with congenital heart disease transition from a paediatric to an adult setting. This is associated with loss-to-follow-up and suboptimal care. Increasing numbers of patients justify a special program. In this study we evaluated the cooperative program between paediatric and adult cardiology departments in a tertiary referral centre. METHODS: In this retrospective study, patients with congenital heart disease with at least one appointment scheduled at the transition program between January 2010 and January 2015 were included. They were seen by a paediatric cardiologist at the age of 15 years in the paediatric department and from age 18 to 25 in the adult department. Demographic and medical data were collected from the electronic patient files. RESULTS: A total of 193 patients (105 males, 88 females) were identified. Sex distribution was almost equal. Most patients were 18-21 years of age. The largest group, 128 patients (67 %), lived within 50 kilometres of our hospital. Paediatric cardiologists referred 157 (81 %) of patients. General practitioners and cardiologists from outside our centre were important referrers for patients lost to follow-up, together accounting for 9 %. A total of 34 (18 %) patients missed an appointment without notification. Repeat offenders, 16 of 34 patients, formed a significant minority within this group. A total of 114 (59 %) patients were attending school, 46 (24 %) were employed, and 33 (17 %) patients were inactive. Activities are in line with capabilities. A nurse practitioner was involved with the 7 % with complex and psychosocial problems. Moderately severe congenital heart defects formed the largest patient category of 102 (53 %) patients. In 3 % of patients the diagnosis had to be revised or was significantly incomplete. In 30 (16 %) patients, cardiac diagnosis was part of a syndrome. Of the 193 patients, 117 (92 %) were in NYHA class I, with 12 (6 %) and 4 (2 %) patients falling into classes II and III, respectively. CONCLUSIONS: A viable transition program can be built by collaboration between paediatric and adult cardiology departments with the same treating physician taking care of patients between 15 and 25 years of age. General practitioners are important in returning lost-to-follow-up patients to specialised care. Nurse practitioners are essential in the care for patients with complex congenital heart disease.

The effect of losartan therapy on ventricular function in Marfan patients with haploinsufficient or dominant negative FBN1 mutations.

BACKGROUND: Mild biventricular dysfunction is often present in patients with Marfan syndrome. Losartan has been shown to reduce aortic dilatation in patients with Marfan syndrome. This study assesses the effect of losartan on ventricular volume and function in genetically classified subgroups of asymptomatic Marfan patients without significant valvular regurgitation. METHODS: In this predefined substudy of the COMPARE study, Marfan patients were classified based on the effect of their FBN1 mutation on fibrillin-1 protein, categorised as haploinsufficient or dominant negative. Patients were randomised to a daily dose of losartan 100 mg or no additional treatment. Ventricular volumes and function were measured by magnetic resonance imaging at baseline and after 3 years of follow-up. RESULTS: Changes in biventricular dimensions were assessed in 163 Marfan patients (48 % female; mean age 38 ± 13 years). In patients with a haploinsufficient FBN1 mutation (n = 43), losartan therapy (n = 19) increased both biventricular end diastolic volume (EDV) and stroke volume (SV) when compared with no additional losartan (n = 24): left ventricular EDV: 9 ± 26 ml vs. -8 ± 24 ml, p = 0.035 and right ventricular EDV 12 ± 23 ml vs. -18 ± 24 ml; p < 0.001 and for left ventricle SV: 6 ± 16 ml vs. -8 ± 17 ml; p = 0.009 and right ventricle SV: 8 ± 16 ml vs. -7 ± 19 ml; p = 0.009, respectively. No effect was observed in patients with a dominant negative FBN1 mutation (n = 92), or without an FBN1 mutation (n = 28). CONCLUSION: Losartan therapy in haploinsufficient Marfan patients increases biventricular end diastolic volume and stroke volume, furthermore, losartan also appears to ameliorate biventricular filling properties.

Mobile health in adults with congenital heart disease: current use and future needs.

OBJECTIVE: Many adults with congenital heart disease (CHD) are affected lifelong by cardiac events, particularly arrhythmias and heart failure. Despite the care provided, the cardiac event rate remains high. Mobile health (mHealth) brings opportunities to enhance daily monitoring and hence timely response in an attempt to improve outcome. However, it is not known if adults with CHD are currently using mHealth and what type of mHealth they may need in the near future. METHODS: Consecutive adult patients with CHD who visited the outpatient clinic at the Academic Medical Center in Amsterdam were asked to fill out questionnaires. Exclusion criteria for this study were mental impairment or inability to read and write Dutch. RESULTS: All 118 patients participated (median age 40 (range 18-78) years, 40 % male, 49 % symptomatic) and 92 % owned a smartphone. Whereas only a small minority (14 %) of patients used mHealth, the large majority (75 %) were willing to start. Most patients wanted to use mHealth in order to receive more information on physical health, and advice on progression of symptoms or signs of deterioration. Analyses on age, gender and complexity of defect showed significantly less current smartphone usage at older age, but no difference in interest or preferences in type of mHealth application for the near future. CONCLUSION: The relatively young adult CHD population only rarely uses mHealth, but the majority are motivated to start using mHealth. New mHealth initiatives are required in these patients with a chronic condition who need lifelong surveillance in order to reveal if a reduction in morbidity and mortality and improvement in quality of life can be achieved.

The revised role of TGF-ß in aortic aneurysms in Marfan syndrome.

BACKGROUND: Recently, we demonstrated that losartan reduced the aortic root dilatation rate (AoDR) in adults with Marfan syndrome (MFS); however, responsiveness was diverse. The aim was to determine the role of transforming growth factor-ß (TGF-ß) as therapeutic biomarker for effectiveness of losartan on AoDR. METHODS: Baseline plasma TGF-ß levels of 22 healthy controls and 99 MFS patients, and TGF-ß levels after 1 month of losartan treatment in 42 MFS patients were measured. AoDR was assessed by magnetic resonance imaging at baseline and after 3 years of follow-up. RESULTS: Patients with MFS had higher TGF-ß levels compared with healthy controls (121 pg/ml versus 54 pg/mL, p = 0.006). After 1 month of therapy, losartan normalised the TGF-ß level in 15 patients (36%); the other 27 patients (64%) showed a significant increase of TGF-ß. After 3 years of losartan therapy, patients with a decrease in TGF-ß had significantly higher AoDR compared with patients with increased TGF-ß (1.5 mm/3 years versus 0.5 mm/3 years, p = 0.04). Patients showing a decrease in TGF-ß after losartan therapy had significantly elevated baseline TGF-ß levels compared with patients with increased TGF-ß (189 pg/ml versus 94 pg/ml, p = 0.05). CONCLUSION: Patients responding to losartan therapy with a reduction of the plasma TGF-ß level had higher baseline TGF-ß levels and a higher AoDR. Most likely, TGF-ß levels may be considered to be a readout of the disease state of the aorta. We propose that increased angiotensin II is the initiator of aorta dilatation and is responsible for increased TGF-ß levels in MFS. The concept of TGF-ß as initiator of aortic dilatation in MFS patients should be nuanced.

Platypnoea-orthodeoxia syndrome, an underdiagnosed cause of hypoxaemia: four cases and the possible underlying mechanisms.

Cardiac platypnoea-orthodeoxia syndrome (POS) is a position-dependent condition of dyspnoea and hypoxaemia due to right-to-left shunting. It often remains unrecognised in clinical practice, possibly because of its complex underlying pathophysiology. We present four consecutive patients with POS and patent foramen ovale (PFO) who underwent a successful percutaneous PFO closure, describe the mechanism of their POS and provide a review of the literature.

Unroofed coronary sinus newly diagnosed in adult patients after corrected congenital heart disease.

Patients with congenital heart disease corrected in early childhood may later in life present with cardiac symptoms caused by other associated congenital anomalies that were initially not diagnosed. Nowadays, several noninvasive imaging modalities are available for the visualisation of cardiac anatomy in great detail. We describe two patients with an unroofed coronary sinus, a rare congenital anomaly which could be diagnosed using a combination of modalities including echocardiography, cardiac CT and cardiac MRI.

Two cases of aorto-right atrial tunnel: clinical presentation, imaging and percutaneous closure.

Communication between the aortic sinus and a cardiac chamber is a rare anomaly that can be diagnosed in children and young adults. We describe two cases with a tunnel between the aortic sinus and right atrium, discuss diagnostic modalities, and review the literature on this anomaly.

Anomalous coronary artery from the pulmonary artery diagnosed in adulthood: a case series on variations of coronary anatomy and the diagnostic value of cardiac magnetic resonance imaging.

Background: Anomalous coronary artery from the pulmonary artery is a rare congenital disorder with high mortality rates in infancy. Adult cases can present with life-threatening arrhythmias and sudden cardiac death. Case summary: We report three cases of adults with anomalous pulmonary origin of each of the main coronary branches. The first patient with an anomalous left coronary artery from the pulmonary artery presented with an out-of-hospital cardiac arrest. The second patient with an anomalous circumflex artery from the pulmonary artery was evaluated for a bicuspid aortic valve and a suspected coronary fistula but was otherwise asymptomatic. The third patient with an anomalous right coronary artery from the pulmonary artery presented with anginal symptoms. In all cases, the diagnosis was made by cardiac computed tomography or coronary angiography. Cardiac magnetic resonance imaging was performed in all patients to guide clinical decision making on surgical or non-invasive management. All patients underwent surgical repair. In two patients, a dual coronary artery system was restored by aortic reimplantation of the anomalous coronary artery. In one patient, aortic reimplantation was unsuccessful due to poor vessel quality and the anomalous coronary artery was ligated. Clinical follow-up during 1.8-9.7 years did not show any cardiovascular complications and all patients are currently alive and asymptomatic. Discussion: Anomalous coronary artery from the pulmonary artery can have various clinical presentations in adulthood. Cardiac magnetic resonance imaging is a useful modality to guide selection of patients who might have symptomatic or prognostic benefit from surgical repair.

Critical appraisal of the revised Ghent criteria for diagnosis of Marfan syndrome.

Marfan syndrome (MFS) is a connective tissue disorder with major features in cardiovascular, ocular and skeletal systems. Recently, diagnostic criteria were revised where more weight was given to the aortic root dilatation. We applied the revised Marfan nosology in an established adult Marfan population to define practical repercussions of novel criteria for clinical practice and individual patients. Out of 180 MFS patients, in 91% (n = 164) the diagnosis of MFS remained. Out of 16 patients with rejected diagnosis, four patients were diagnosed as MASS (myopia, mitral valve prolapse, borderline non-progressive aortic root dilatation, skeletal findings and striae) phenotype, three as ectopia lentis syndrome and in nine patients no alternative diagnosis was established. In 13 patients, the diagnosis was rejected because the Z-score of the aortic root was <2, although the aortic diameter was larger than 40 mm in six of them. In three other patients, the diagnosis of MFS was rejected because dural ectasia was given less weight in the revised nosology. Following the revised Marfan nosology, the diagnosis of MFS was rejected in 9% of patients, mostly because of the absence of aortic root dilatation defined as Z-score ≥2. Currently used Z-scores seem to underestimate aortic root dilatation, especially in patients with large body surface area (BSA). We recommend re-evaluation of criteria for aortic root involvement in adult patients with a suspected diagnosis of MFS.

The aortic root in repaired tetralogy of Fallot: Serial measurements and impact of losartan treatment.

BACKGROUND: Aortic root dilatation is common in adults with repaired tetralogy of Fallot (rTOF) and might lead to aortic dissection. However, little is known on progression of aortic dilatation and the effect of pharmaceutical treatment. This study aims to determine factors associated with aortic growth and investigate effects of losartan. METHODS AND RESULTS: We performed a prespecified analysis from the 1:1 randomized, double-blind REDEFINE trial. Aortic root diameters were measured at baseline and after 2.0 ± 0.3 years of follow-up using cardiovascular magnetic resonance (CMR) imaging. A total of 66 patients were included (68% men, age 40 ± 12 years, baseline aortic root 37 ± 6 mm, 32% aortic dilatation (>40 mm)). There was a trend towards slow aortic root growth (+0.6 ± 2.3 mm after two years, p = 0.06) (n = 60). LV stroke volume was the only factor associated with both a larger baseline aortic root (ß: 0.09 mm/ml (95% C.I.:0.02, 0.15), p = 0.010) and with aortic growth during follow-up (ß: 0.04 mm/ml (95% C.I.:0.005, 0.066), p = 0.024), after correction for age, sex, and body surface area using linear regression analysis. No treatment effect of losartan was found (p = 0.17). CONCLUSIONS: Aortic root dilatation was present in about one-third of rTOF patients. A larger LV stroke volume was associated with both a larger baseline aortic root and ongoing growth. Our findings provide no arguments for lower aortic diameter thresholds for prophylactic surgery compared to the general population.

Paracrine regulation of germinal center B cell adhesion through the c-met-hepatocyte growth factor/scatter factor pathway.

T cell-dependent humoral immune responses are initiated by the activation of naive B cells in the T cell areas of the secondary lymphoid tissues. This primary B cell activation leads to migration of germinal center (GC) cell precursors into B cell follicles where they engage follicular dendritic cells (FDC) and T cells, and differentiate into memory B cells or plasma cells. Both B cell migration and interaction with FDC critically depend on integrin-mediated adhesion. To date, the physiological regulators of this adhesion were unkown. In the present report, we have identified the c-met-encoded receptor tyrosine kinase and its ligand, the growth and motility factor hepatocyte growth factor/scatter factor (HGF/SF), as a novel paracrine signaling pathway regulating B cell adhesion. We observed that c-Met is predominantly expressed on CD38(+)CD77(+) tonsillar B cells localized in the dark zone of the GC (centroblasts). On tonsil B cells, ligation of CD40 by CD40-ligand, induces a transient strong upregulation of expression of the c-Met tyrosine kinase. Stimulation of c-Met with HGF/SF leads to receptor phosphorylation and, in addition, to enhanced integrin-mediated adhesion of B cells to both VCAM-1 and fibronectin. Importantly, the c-Met ligand HGF/SF is produced at high levels by tonsillar stromal cells thus providing signals for the regulation of adhesion and migration within the lymphoid microenvironment.

Relation of phenotype evolution of HIV-1 to envelope V2 configuration.

Biological variability of human immunodeficiency virus type-1 (HIV-1) is involved in the pathogenesis of acquired immunodeficiency syndrome (AIDS). Syncytium-inducing (SI) HIV-1 variants emerge in 50 percent of infected individuals during infection, preceding accelerated CD4+ T cell loss and rapid progression to AIDS. The V1 to V2 and V3 region of the viral envelope glycoprotein gp120 contained the major determinants of SI capacity. The configuration of a hypervariable locus in the V2 domain appeared to be predictive for non-SI to SI phenotype conversion. Early prediction of HIV-1 phenotype evolution may be useful for clinical monitoring and treatment of asymptomatic infection.

Transvenous pacing after the Mustard procedure: considering the complications.

Disturbances of rhythm and conduction in patients undergoing surgery for transposition of the great arteries have been widely reported. Some of these patients require implantation of a permanent pacemaker, especially those in whom symptomatic sick sinus syndrome is diagnosed. We present the case of a 29-year-old male corrected with a Mustard procedure, who received a pacemaker for progressive atrioventricular conduction disturbances and sinus node dysfunction, and we review the possible complications associated with transvenous pacemaker implantation in these patients. (Neth Heart J 2007;15:387-89.).

Clinical course of tricuspid regurgitation in repaired tetralogy of Fallot.

BACKGROUND: Little is known on the clinical course of tricuspid regurgitation (TR) in patients with repaired tetralogy of Fallot (rTOF) and which patients are at particular risk. This study aims to determine TR course, characteristics associated with TR progression, and the prognostic relevance of TR in rTOF patients. METHODS: In this dualcenter cohort study, rTOF patients from a prospective national registry with ≥1 cardiac magnetic resonance imaging study and ≥2 echocardiograms available were included. Clinical and imaging data were collected. Cox hazards regression analysis was used to assess patient characteristics associated with progression to severe TR and whether severe TR was associated with the combined clinical endpoint of tachyarrhythmia, heart failure, and death, as time-dependent factor. RESULTS: A total of 216 patients were included (57% men, age 34±12years); 11 patients (5%) had severe TR at baseline. During 7.6±3.5years of follow-up, progression to severe TR occurred in 15 patients (7%). NYHA class ≥2 (HR 5.38, 95%-C.I. 1.91-15.16, p=0.001) and moderate baseline TR (HR 13.10, 95%-C.I. 2.95-58.21, p=0.001) were independently associated with progression to severe TR. Adverse events occurred in 47 patients (22%). The occurrence of severe TR was independently associated with adverse events (HR 3.48, 95%-C.I. 1.68-7.21, p=0.001). CONCLUSIONS: In this study, severe TR was present in 12% of adult rTOF patients during 7.6years, and progression to severe TR was most likely in symptomatic patients with moderate baseline TR. In these patients, close surveillance is warranted, because the occurrence of severe TR was associated with worse prognosis.

The influence of aging and aortic stiffness on permanent dilation and breaking stress of the thoracic descending aorta.

OBJECTIVE: To assess the influence of aging and aortic stiffness on the extent of irreversible deformation and breaking stress of the human thoracic aorta. METHODS: From 14 human heart valve donors without aortic disease (mean age 35 years, range 8-59 years), 14 intact segments of the thoracic descending aorta were studied within 48 h after cardiac arrest. In an experimental setup, the segments were submitted to increasing hydrostatic pressure loads, both statically and dynamically, while radius and wall thickness were monitored echocardiographically. Pressure-radius curves were constructed. Radius and wall thickness were determined at a pressure of 100 mmHg. Radius at elastin resting length and collagen recruitment pressure (Pcol, mmHg) were derived from the pressure-radius relationship and stress-strain curves were constructed to yield Young's moduli of elastin and collagen. Distensibility (D, mmHg-1) was determined while loading the segment with a sinusoidal pressure wave of 120/50 mmHg at both 0.5 and 1 Hz. Subsequently increasing static pressure loads of 400, 800, 1200 and 1600 mmHg were applied. After each pressure load, the increase in aortic radius at a pressure of 100 mmHg (Rinc) was determined. The experiment continued until rupture occurred and breaking stress (sigma break, N m-2) was calculated, donor age and aortic stiffness were correlated with Rinc and sigma break of the aortic segments. RESULTS: Mean breaking stress of the 14 segments was 2.7 x 10(6) N m-2. Breaking stress was negatively correlated with age (r2 = 0.66) and positively with D (r2 = 0.44) and with Pcol (r2 = 0.18). Seven segments survived a pressure load of 800 mmHg, in these vessels, the extent of irreversible dilation was positively correlated with age (r2 = 0.42) and negatively with D (r2 = 0.40) and Pcol (r2 = 0.40). CONCLUSION: Permanent deformation and rupture of the human thoracic aorta following pressure overload are influenced by age, distensibility and collagen recruitment pressure.

Cardiovascular imaging in children and adults following Kawasaki disease.

Kawasaki disease (KD) is a paediatric vasculitis with coronary artery aneurysms (CAA) as its main complication. Two guidelines exist regarding the follow-up of patients after KD, by the American Heart Association and the Japanese Circulation Society. After the acute phase, CAA-negative patients are checked for cardiovascular risk assessment or with ECG and echocardiography until 5 years after the disease. In CAA-positive patients, monitoring includes myocardial perfusion imaging, conventional angiography and CT-angiography. However, the invasive nature and high radiation exposure do not reflect technical advances in cardiovascular imaging. Newer techniques, such as cardiac MRI, are mentioned but not directly implemented in the follow-up. Cardiac MRI can be performed to identify CAA, but also evaluate functional abnormalities, ischemia and previous myocardial infarction including adenosine stress-testing. Low-dose CT angiography can be implemented at a young age when MRI without anaesthesia is not feasible. CT calcium scoring with a very low radiation dose can be useful in risk stratification years after the disease. By incorporating newer imaging techniques, detection of CAA will be improved while reducing radiation burden and potential complications of invasive imaging modalities. Based on the current knowledge, a possible pathway to follow-up patients after KD is introduced. Key Points • Kawasaki disease is a paediatric vasculitis with coronary aneurysms as major complication. • Current guidelines include invasive, high-radiation modalities not reflecting new technical advances. • Cardiac MRI can provide information on coronary anatomy as well as cardiac function. • (Low-dose) CT-angiography and CT calcium score can also provide important information. • Current guidelines for follow-up of patients with KD need to be revised.

Changes in aortic distensibility and pulse wave velocity assessed with magnetic resonance imaging following beta-blocker therapy in the Marfan syndrome.

It has been shown that beta-adrenergic blocking agents may reduce the rate of aortic root dilation and the development of aortic complications in patients with the Marfan syndrome. This may be due to beta-blocker-induced changes in aortic stiffness, of which distensibility and pulse wave velocity are in vivo measurable derivatives. We studied changes in distensibility at 4 levels of the aorta and pulse wave velocity along the entire aorta after 2 weeks of beta-blocker therapy in 6 Marfan syndrome patients and in 6 healthy volunteers, using magnetic resonance imaging (MRI) combined with brachial artery blood pressure measurements. In both groups, mean blood pressure decreased significantly (Marfan: 86 +/- 6 vs 78 +/- 5 mm Hg, p <0.05; control: 80 +/- 8 vs 73 +/- 3 mm Hg, p <0.05) (all data expressed as mean +/- 1 SD). At baseline, the Marfan syndrome patients exhibited decreased distensibility at the level of the ascending aorta (2 +/- 1 vs 6 +/- 2 10(-3)mm Hg(-1), p <0.01) and increased pulse wave velocity (6.2 +/- 0.4 vs 3.9 +/- 0.4 ms(-1), p <0.01) compared with control subjects. Only the Marfan syndrome patients had a significant increase in aortic distensibility at multiple levels and a significant decrease in pulse wave velocity after beta-blocker therapy (ascending aorta distensibility: 2 +/- 1 vs 4 +/- 1 10(-3)mm Hg(-1), p <0.05; abdominal aorta distensibility: 5 +/- 2 vs 8 +/- 3 10(-3)mm Hg(-1), p <0.05; pulse wave velocity: 6.2 +/- 0.4 vs 5.0 +/- 1.0 ms(-1), p <0.05). Thus, aortic stiffness in Marfan syndrome, together with mean blood pressure, is reduced by beta-blocker therapy, and MRI is well suited to detect these changes by measuring distensibility and pulse wave velocity.

Potent inhibition of replication of primary HIV type 1 isolates in peripheral blood lymphocytes by negatively charged human serum albumins.

We previously reported the antiviral capacity of human serum albumin (HSA), which was modified by the introduction of a single (Suc-HSA) or two carboxylic groups (Aco-HSA) per lysine residue, yielding strongly negatively charged polypeptides. Here we report the antiviral effect of these modified HSAs on replication of primary HIV-1 isolates that differed with respect to syncytium-inducing (SI) capacity and cell tropism. Both Suc-HSA and Aco-HSA potently inhibited replication of primary HIV-1 variants, independent of the SI capacity of the HIV-1 variant, with IC50 values in the range of 50 to 187 microg/ml. The inhibition of the formation of syncytia and the absence of proviral DNA products in cells inoculated with HIV-1 in the presence of Suc-HSA or Aco-HSA pointed to interference at an early level in the virus replication cycle. The inhibitory capacity of Suc-HSA and Aco-HSA on primary HIV-1 variants suggests that these agents are potential candidates for use in antiviral therapy in HIV-infected individuals.