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ID naloge: 90 Letnik: 2000 Predmet: interna medicina
Sprememba vazomotorne funkcije koronarnih in perifernih arterij pri bolnikih s koronarno aterosklerozo
Avtor: Miha Cercek
Mentor: prof. dr. Igor Kranjec
Izhodišca Razvoj ateroskleroticnega procesa sproži poškodba endotela in posledicna okvara njegove funkcije. Okvara endotelne funkcije se odraža med drugim z moteno od endotela odvisno vazomotoriko (EOV). Mnoge raziskave so pokazale, da dejavniki, ki sicer preko posredovanja zdravega endotela sprožijo vazodilatacijo, že v zgodnjih fazah ateroskleroticnega procesa povzrocijo oslabljen oziroma celo nasproten odziv, to je vazokonstrikcijo. Za normalno vazoreaktivnost je potrebno tudi normalno delovanje žilnih gladkomišicnih celic (GMC). V procesu aterogeneze pride tudi do okvare funkcije GMC, ki jo lahko opredelimo z oceno od endotela neodvisne vazomotorike (ENV). ENV sprožijo dejavniki, kateri delujejo neposredno na GMC, brez vpliva endotela. Mnenja o tem, kdaj v procesu bolezni pride do okvare GMC, so deljena. Prav tako ni jasno ali je prizadetost ENV generalizirana, kar velja za prizadetost EOV, ali je omejena zgolj na arterije, kjer je prišlo do tvorbe ateroskleroticnega plaka. Z raziskavo smo želeli primerjati EOV in ENV, kot tudi opredeliti razširjenost njune prizadetosti pri bolnikih s koronarno srcno boleznijo.
Metode V raziskavo smo vkljucili 15 bolnikov s koronarno srcno boleznijo. EOV smo ocenili s pomocjo testiranja s hladom (cold pressor test, CPT), na brahialnih arterijah pa še dodatno s testom z zažemom. ENV smo ocenili s pomocjo nitroglicerinskega testa (nitroglicerin 200mg bolus intrakoronarno in nitroglicerin 0,4mg sublingualno). Razsežnost ateroskleroticnega procesa in spremembe žilne svetline pri posameznih testih smo na koronarnih arterijah (arteriji LAD in LCX) kvantitativno opredelili angiografsko, na perifernih arterijah (brahialna arterija) pa ultrasonografsko.
Rezultati Po izvedbi CPT je prišlo do porasta frekvence srcnega utripa in arterijskega krvnega tlaka ter do konstrikcije koronarnih arterij, premer brahialne arterije pa se ni statisticno znacilno spremenil. Po nitroglicerinu je prišlo do padca arterijskega krvnega tlaka in porasta srcne frekvence ter do vazodilatacije v vseh opazovanih arterijskih povirjih. Odziv na provokacijske teste je bil na koronarnih arterijah bolj izrazit na mestih zožitev kot na neprizadetih odsekih. Opazili smo pozitivno korelacijo med prizadetostjo EOV brahialne arterije (test z zažemom) in arterije LAD (CPT). V vseh arterijskih povirjih je EOV pozitivno korelirala z ENV. Dejavniki tveganja so bili povezani s prizadetostjo EOV (arterijska hipertenzija, hiperlipidemija, kajenje), kot tudi s prizadetostjo ENV (družinska obremenjenost).
Zakljucki Ugotovili smo, da je prizadetost ENV generalizirana. Prisotna je že zgodaj v procesu ateroskleroze ter korelira s prizadetostjo EOV.
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[Abstract / English version]
Change in coronary and peripheral vascular function in patients with coronary atherosclerosis
Author: Miha Cercek
Mentor: prof. dr. Igor Kranjec
Background Endothelial injury and the consequent endothelial dysfunction initiate the atherosclerotic process. One of the manifestations of endothelial dysfunction is attenuation of endothelium dependant vasomotion (EOV). Many studies showed that factors which induce dilator response in presence of intact endothelium, cause less vasodilation and even vasoconstriction in patients with atherosclerosis. This impairment of EOV was observed already in early phases of atherosclerotic process. It seems to involve the entire arterial tree. Function of vascular smooth muscle is also impaired in atherosclerosis. The degree of the impairment can be determined by the evaluation of endothelium non-dependant vasomotion (ENV). ENV is induced by factors acting directly on the vascular smooth muscle, without any endothelial involvement. It is not clear at which stage of atherosclerotic process the ENV becomes impaired. It is also not clear whether the impairment of ENV is generalised or limited to the sites of atherosclerotic plaques. In our study, we compared EOV with ENV, and evaluated the generalisation of their impairment in patients with coronary artery disease.
Methods We examined 15 patients with coronary artery disease. EOV was assessed with the cold pressor test (CPT) and with the cuff dilation test, while nitroglycerin (200mg intracoronary bolus injection and 0,4mg sublingually) was used to test ENV. The extent of the atherosclerotic process and the vascular response to provocative stimuli of coronary arteries were determined angiographically, while ultrasound measurements were performed for evaluating the changes in brachial artery.
Results CPT caused elevation of heart rate and arterial blood pressure. Coronary arteries constricted in response to CPT, while brachial artery diameter did not change significantly. Aplication of nitroglycerin lowered arterial blood pressure and increased heart rate. All studied arteries dilated in response to nitroglycerin. Coronary artery response to provocative stimuli was more pronounced at sites of stenosis then at unaffected segments of the vessel. The EOV impairment of brachial artery (cuff dilation) correlated with the EOV impairment of LAD artery (CPT). We observed correlation of EOV with ENV in all studied arteries. The risk factors were linked to both, the EOV impairment (arterial hypertension, hyperlipidemia, smoking) and the ENV impairment (disease burden in the family).
Conclusions We observed that the impairment of ENV is generalised. It develops early in the atherosclerotic process and correlates with the impairment of EOV.
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