 Potential emerging therapeutic strategies to prevent
restenosis in the peripheral vasculature.
Reference: Cathet Cardiovasc Intervent 2002;56:421-431.
Despite the availability of antiplatelet and antithrombotic therapies,
recent advances in catheter and stent technology and improved operator
skill, restenosis remains the most frequent problem associated with
percutaneous and surgical revascularization interventions for both coronary
and peripheral arterial disease. Prevention of restenosis in the coronary
vasculature has been demonstrated with cilostazol, trapidil, probucol,
tranilast, nitric oxide donors, and clopidogrel. Given the similarities in
revascularization procedures and in the pathophysiology of restenosis, it
is possible that these results may be extrapolated to the setting of
restenosis in the peripheral vasculature, making trials with these agents
imperative. Several new agents have shown promising
preliminary results for the prevention of restenosis in the peripheral
vasculature, including cilostazol, low-molecular-weight heparins, and
elastase. Several nonpharmacologic treatment modalities are also under
study to prevent peripheral and coronary restenosis and have shown
favorable initial results. These include endovascular radiation
brachytherapy, arterial gene therapy, photoangioplasty, and several novel
treatment delivery systems.
Prevention of
ventricular fibrillation by cilostazol, an oral phosphodiesterase
inhibitor, in a patient with Brugada syndrome.
Reference:J Cardiovasc Electrophysiol 2002 Jul;13(7):698-701
We report the case of 67-year-old man with Brugada syndrome, in whom daily
episodes of ventricular fibrillation (VF) occurred every early morning for
4 days. The episodes of VF were completely prevented by an oral
administration of cilostazol, a phosphodiesterase inhibitor. This effect
was confirmed by the on-and-off challenge test, in which discontinuation
of the drug resulted in recurrence of VF and resumption of the drug again
prevented VF. This effect may be
related to the suppression of I(to) secondary to the increase in heart
rate and/or to an increase in Ca2+ current (I(Ca)) due to an elevation of
intracellular cyclic AMP concentration via inhibition of phosphodiesterase
activity. This drug might have an anti-VF potential in patients with
Brugada syndrome.
The severity
of muscle ischemia during intermittent claudication.
Reference: J Vasc Surg 2002;36(1):89-93.
PURPOSE: The degree of ischemia during intermittent claudication is
difficult to quantify. We evaluated calf muscle ischemia during exercise
in patients with claudication with near infrared spectroscopy.
METHODS: A Critikon Cerebral Redox
Model 2001 (Johnson & Johnson Medical, Newport, Gwent, United Kingdom) was
used to measure calf muscle deoxygenated hemoglobin (HHb), oxygenated
hemoglobin (O(2)Hb), and total hemoglobin levels and oxygenation index (HbD;
HbD = O(2)Hb - HHb) in 16 patients with claudication and in 14 control
subjects before, during, and after walking on a treadmill for 1 minute
(submaximal exercise). These measures were
repeated after a second maximal exercise in patients with claudication and
after 7 minutes walking in control subjects. Near-infrared spectroscopy
readings during maximal exercise were then compared with a model of total
ischemia induced with tourniquet in 16 young control subjects.
RESULTS: Total hemoglobin level
changed little during exercise in both patients with claudication and
control subjects. HHb levels rose, and O(2)Hb level and HbD falls were
more pronounced in patients with claudication than in control subjects
after submaximal and maximal exercise. During maximal exercise, HbD fell
markedly by a median (interquartile range) of 210.5 micromol/cm
(108.2 to 337.0 micromol/cm) in patients with claudication compared with
66.0 micromol/cm (44.0 to 101.0 micromol/cm) in elderly control subjects
and 41.0 micromol/cm (36.0 to 65.0 micromol/cm) in young control subjects
(P <.001). This fall also was greater than the HbD fall induced with
tourniquet ischemia at 90.8 micromol/cm (57.6 to 126.2 micromol/cm; P
=.006).
CONCLUSION: Hemoglobin desaturation
in exercising calf muscle is profound in patients with claudication,
considerably greater even than that induced with three minutes of
tourniquet occlusion. Further studies are necessary to investigate the
relationship between the inflammatory response and near-infrared
spectroscopy during exercise in patients with claudication.
Exercise
capacity and Doppler pressure measurements in symptomatic
peripheral arterial obstructive disease.
Reference: Vasa 2002;31(2):107-10.
BACKGROUND: Doppler pressure measurements are a useful diagnostic tool in
peripheral arterial obstructive disease. The aim of our study was to
determine whether these pressure values do predict the degree of
impairment of the walking capacity in symptomatic patients.
PATIENTS AND METHODS: We compared
the claudication distances (CDI: initial claudication distance, CDA:
absolute claudication distance) of 939 patients (63 +/- 11 years) with
stable intermittent claudication (Fontaine IIb) with the ankle pressure
values at rest (APR) and after exercise (APE), with the ankle/brachial
pressure index at rest (ABIR) and after exercise (ABIE), and with the
ratio
(ABIRATIO = ABIE/ABIR). Ankle systolic pressures were obtained using an 8
MHz Doppler probe. CD was measured by a treadmill test at constant-load
conditions (3 km/hr; inclination 12%). Brachial systolic pressures were
obtained using an automated blood pressure monitor. The values of the
objectively worse leg were correlated with CDI and CDA.
RESULTS: Low Doppler pressure values
were not accompanied by significantly shorter walking distances in
symptomatic patients. The resting pressure values (APR, ABIR) did not
correlate with the claudication distances (CDI: 54 +/- 31 m; CDA: 87 +/-
41 m). For the exercise values (APE, ABIE), even a very slight
inverse correlation with the claudication distances was found. In
addition, the correlation between the pressure index ratio and the walking
distances (ABIRATIO vs. CDI: r = -0.25, p < 0.01; ABIRATIO vs. CDA: r =
-0.20, p < 0.01) was inverse, too, but slightly more pronounced.
CONCLUSIONS: In patients with
intermittent claudication the ankle artery pressures and the indices
derived from these pressure values do not predict the walking distance.
Therefore, the decision for angioplasty or bypass surgery should be made
with regards to the impairment of quality of life rather than Doppler
pressure values.
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Volume 5, Number 8: August 2002 
