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Marta Francesca Brancati, 1 Francesco Burzotta, 2 Carlo Trani, 2 Ornella Leonzi, 1 Claudio Cuccia, 1 Filippo Crea2 1 Sashen Ilimin Zuciya, Asibitin Gidauniyar Poliambulanza, Brescia, 2 Sashen Ilimin Zuciya, Jami'ar Katolika ta Zuciya Mai Tsarki ta Rome, Italiya Takaitaccen Bayani: Magungunan da ke ɗauke da ƙwayoyin cuta (DES) suna rage iyakokin ƙwayoyin cuta na ƙarfe (BMS) bayan an yi musu tiyatar zuciya ta hanyar tiyatar zuciya ta hanyar tiyata. Duk da haka, duk da cewa gabatar da DES na ƙarni na biyu ya nuna cewa ya daidaita wannan lamari idan aka kwatanta da DES na ƙarni na farko, akwai damuwa mai tsanani game da yiwuwar rikice-rikicen dasa stent a ƙarshen lokaci, kamar thrombosis na stent (ST) da kuma cire stent. Stenosis (ISR).ST wani lamari ne mai yuwuwar bala'i wanda aka rage shi sosai ta hanyar ingantaccen stenting, sabbin ƙira na stent, da kuma maganin hana platelet guda biyu. Ana binciken ainihin hanyar da ke bayanin faruwarsa, kuma hakika, abubuwa da yawa suna da alhakin. A baya an yi la'akari da ISR a cikin BMS a matsayin yanayi mai dorewa tare da farkon kololuwar hyperplasia na ciki (a cikin watanni 6) sannan kuma lokacin komawa baya na sama da shekara 1. Sabanin haka, duka nazarin asibiti da na histological na DESs sun nuna shaidar ci gaban neointimal mai ɗorewa a lokacin bin diddigin na dogon lokaci, wani lamari da aka sani da abin da ya faru na "kamawa a ƙarshe". Ra'ayin cewa ISR wani yanayi ne na asibiti mai sauƙi kwanan nan ya fuskanci ƙalubale ta hanyar shaida cewa marasa lafiya da ISR na iya haifar da cututtukan zuciya mai tsanani. Hoton cikin ƙwayar cuta wata dabara ce mai mamayewa wacce za ta iya gano plaques na atherosclerotic da fasalulluka na warkar da tasoshin bayan stent; Sau da yawa ana amfani da shi don kammala binciken cututtukan zuciya da hanyoyin shiga tsakani. Ana ɗaukar hoton haɗin gwiwar gani a cikin lanƙwasa a matsayin mafi kyawun dabarar hoto. Idan aka kwatanta da na'urar duban dan tayi ta cikin jijiyoyin jini, yana ba da mafi kyawun ƙuduri (aƙalla sau 10), yana ba da damar cikakken bayanin tsarin saman bangon jijiyoyin jini. Nazarin hotunan In vivo wanda ya yi daidai da binciken histological ya nuna cewa kumburi na yau da kullun da/ko rashin aikin endothelial na iya haifar da neo-atherosclerosis na ƙarshen mataki a cikin BMS da DES. Saboda haka, neo-atherosclerosis ya zama babban abin zargi a cikin pathogenesis na ƙarshen stent failure. Kalmomi masu mahimmanci: stent na zuciya, stent thrombosis, restenosis, neoatherosclerosis
Tsarin tiyatar zuciya ta Percutaneous (PCI) tare da dasa stent shine hanyar da aka fi amfani da ita don magance cututtukan jijiyoyin zuciya masu alama, kuma dabarar tana ci gaba da bunƙasa.1 Duk da cewa stents masu ɗauke da magunguna (DES) suna rage iyakokin stents na ƙarfe (BMSs), matsaloli na ƙarshen lokaci kamar stent thrombosis (ST) da in-stent restenosis (ISR) na iya faruwa tare da dasa stent. , akwai damuwa mai tsanani.2-5
Idan ST wani lamari ne mai yuwuwar faruwa, fahimtar cewa ISR cuta ce mai sauƙi, kwanan nan an ƙalubalantar ta ta hanyar shaidar cutar zuciya mai tsanani (ACS) a cikin marasa lafiya na ISR.4
A yau, ana ɗaukar hoton da ke haɗa ƙwayoyin ido ta hanyar intracoronary optical coherence tomography (OCT) 6-9 a matsayin dabarar daukar hoto ta zamani, wadda ke ba da haske mafi kyau fiye da nazarin hotunan da ke cikin jijiyoyin jini (IVUS), wanda ya yi daidai da binciken da aka yi a histological, yana nuna wata hanyar "sabuwar" amsawar jijiyoyin jini bayan dasa stent, tare da de novo "neoatherosclerosis" a cikin BMS da DES.
A shekarar 1964, Charles Theodore Dotter da Melvin P Judkins sun bayyana angioplasty na farko. A shekarar 1978, Andreas Gruntzig ya yi angioplasty na balan-balan na farko (tsohon balan-balan angioplasty); magani ne mai sauyi amma yana da illa ga rufewar jijiyoyin jini da kuma sake dawowa.13 Wannan ya haifar da gano angioplasty na zuciya: Puel da Sigwart sun yi amfani da angioplasty na zuciya na farko a shekarar 1986, suna samar da angioplasty don hana rufewar jijiyoyin jini da kuma komawar systolic a ƙarshen lokaci.14 Kodayake waɗannan angioplasty na farko sun hana rufewar jijiyoyin kwatsam, sun haifar da mummunan lalacewar endothelial da kumburi. Daga baya, gwaje-gwaje biyu masu mahimmanci, Gwajin Stent na Belgium-Holland 15 da Nazarin Stent Restenosis na 16, sun ba da shawarar amincin angioplasty tare da maganin antiplatelet guda biyu (DAPT) da/ko dabarun turawa masu dacewa.17,18 Bayan waɗannan gwaje-gwajen, an sami ƙaruwa sosai a yawan PCI da aka yi.
Duk da haka, an gano matsalar hyperplasia ta in-stent neointimal hyperplasia bayan sanya BMS cikin sauri, wanda ya haifar da ISR a cikin 20%–30% na raunukan da aka yi wa magani. A shekara ta 2001, an gabatar da DES19 don rage buƙatar restenosis da sake shiga tsakani. DESs ta ƙara kwarin gwiwar likitocin zuciya, tana ba da damar ƙara yawan raunuka masu rikitarwa waɗanda aka yi tunanin a baya za a magance su ta hanyar grafting na jijiyoyin zuciya. A shekara ta 2005, kashi 80%–90% na dukkan PCI suna tare da DES.
Komai yana da nasa matsalolin, kuma tun daga shekarar 2005, damuwa game da amincin DES na "ƙarni na farko" ya ƙaru, kuma an haɓaka da kuma gabatar da sabbin stents kamar 20,21.22 Tun daga lokacin, ƙoƙarin inganta aikin stent ya bunƙasa cikin sauri, kuma an ci gaba da gano sabbin fasahohi masu ban mamaki kuma ana kawo su kasuwa cikin sauri.
BMS bututu ne mai siririn waya. Bayan ƙwarewa ta farko da dutsen "Wall", dutsen Gianturco-Roubin da dutsen Palmaz-Schatz, yanzu akwai BMS daban-daban.
Zane-zane guda uku daban-daban suna yiwuwa: na'urar coil, bututun raga da bututun rami. Zane-zanen na'urar coil suna da wayoyi ko tsiri na ƙarfe waɗanda aka samar zuwa siffar na'urar coil mai zagaye; zane-zanen na'urar bututun rami suna da wayoyi da aka naɗe tare a cikin raga don samar da bututu; zane-zanen na'urar bututun rami sun ƙunshi bututun ƙarfe waɗanda aka yanke ta laser. Waɗannan na'urori sun bambanta a cikin abun da ke ciki (bakin ƙarfe, nichrome, cobalt chrome), ƙirar tsari (tsarin strut daban-daban da faɗi, diamita da tsayi, ƙarfin radial, radiance) da tsarin isarwa (mai faɗaɗa kai ko mai faɗaɗa balan-balan).
Gabaɗaya, sabon BMS ya ƙunshi ƙarfe mai kama da cobalt-chromium, wanda ke haifar da siraran struts tare da ingantaccen sauƙin kewayawa, yana kiyaye ƙarfin injina.
Sun ƙunshi wani dandamali na ƙarfe (yawanci bakin ƙarfe) kuma an shafa su da wani polymer wanda ke fitar da magungunan hana yaɗuwa da/ko kumburi.
An ƙera Sirolimus (wanda aka fi sani da rapamycin) a matsayin maganin kashe ƙwayoyin cuta. Tsarin aikinsa ya samo asali ne daga toshe ci gaban zagayowar ƙwayoyin halitta ta hanyar toshe canjin yanayin daga matakin G1 zuwa matakin S da kuma hana samuwar neointima. A shekara ta 2001, ƙwarewar "farko a cikin ɗan adam" tare da SES ta nuna sakamako mai kyau, wanda ya haifar da ci gaban Cypher stent.23 Manyan gwaje-gwaje sun nuna ingancinsa wajen hana ISR.24
An fara amincewa da Paclitaxel don maganin ciwon daji na ovarian, amma ƙarfinsa na cytostatic - maganin yana daidaita microtubules yayin mitosis, yana haifar da dakatar da zagayowar ƙwayoyin halitta kuma yana hana samuwar ƙwayoyin halitta - ya sanya shi mahaɗin Taxus Express PES. Gwaje-gwajen TAXUS V da VI sun nuna ingancin PES na dogon lokaci a cikin cututtukan jijiyoyin zuciya masu haɗari da rikitarwa.25,26 TAXUS Liberté na gaba ya nuna dandamalin bakin ƙarfe don sauƙin isarwa.
Shaidun ƙarshe daga bita guda biyu na tsari da kuma nazarin meta-nazari sun nuna cewa SES tana da fa'ida fiye da PES saboda ƙarancin ƙimar ISR da sake fasalin jijiyoyin jini (TVR), da kuma yanayin ƙaruwar bugun zuciya mai tsanani (AMI) a cikin ƙungiyar PES. 27,28
Na'urorin ƙarni na biyu suna da ƙarancin kauri na strut, ingantaccen sassauci/samun damar isar da sako, haɓaka bayanan polymer biocompatibility/drug exlution, da kuma kyakkyawan tsarin sake-endothelialization. A aikace na zamani, su ne mafi ci gaba a cikin ƙira na DES da manyan stents na zuciya da aka dasa a duniya.
Taxus Elements wani ci gaba ne na musamman tare da wani polymer na musamman wanda aka tsara don haɓaka fitowar da wuri da kuma sabon tsarin strut na platinum-chromium wanda ke samar da siraran struts da ingantaccen rediyo. Gwajin PERSEUS 29 ya lura da irin wannan sakamako tsakanin Element da Taxus Express na tsawon watanni 12. Duk da haka, gwaje-gwajen da ke kwatanta yew elements da sauran ƙarni na biyu DES ba su da yawa.
An gina zotarolimus-eluting stent (ZES) Endeavor ne akan wani dandamali mai ƙarfi na cobalt-chromium stent tare da sassauci mafi girma da ƙaramin girman stent strut. Zotarolimus analog ne na sirolimus tare da irin wannan tasirin hana garkuwar jiki amma an inganta lipophilicity don haɓaka wurin bangon jijiyoyin jini. ZES yana amfani da sabon murfin polymer na phosphorylcholine wanda aka tsara don haɓaka daidaiton biocompatibility da rage kumburi. Yawancin magunguna ana fitar da su a lokacin farkon rauni, sannan a gyara jijiyoyin jini. Bayan gwajin ENDEAVOR na farko, gwajin ENDEAVOR III na gaba ya kwatanta ZES da SES, wanda ya nuna asarar lumen mafi girma da ISR amma ƙarancin manyan abubuwan da suka faru na zuciya da jijiyoyin jini (MACE) fiye da SES.30 Gwajin ENDEAVOR IV, wanda ya kwatanta ZES da PES, ya sake gano mafi yawan ISR, amma ƙarancin yawan AMI, a bayyane yake daga ST mai ci gaba sosai a cikin ƙungiyar ZES.31 Duk da haka, gwajin PRECTE ya kasa nuna bambanci a cikin ƙimar ST tsakanin Endeavor da Cypher stents.32
Endeavor Resolute wani ingantaccen sigar Endeavor stent ne tare da sabon polymer mai matakai uku. Sabuwar Resolute Integrity (wani lokacin ana kiranta DES na ƙarni na uku) ta dogara ne akan sabon dandamali tare da ƙarfin isarwa mafi girma (dandalin Integrity BMS), kuma sabon polymer mai matakai uku mai jituwa da halittu, zai iya danne martanin kumburi na farko da kuma kawar da mafi yawan maganin a cikin kwanaki 60 masu zuwa. Wani gwaji da aka kwatanta Resolute da Xience V (everolimus-eluting stent [EES]) ya nuna rashin ƙarancin tsarin Resolute dangane da mutuwa da gazawar rauni da aka yi niyya.33,34
Everolimus, wani abu da aka samo daga sirolimus, shi ma wani abu ne da ke hana zagayowar ƙwayoyin halitta da ake amfani da shi wajen haɓaka Xience (dandalin Multi-link Vision BMS)/Promus (dandalin Platinum Chromium) EES. Gwajin SPIRIT 35-37 ya nuna ingantaccen aiki da rage MACE tare da Xience V idan aka kwatanta da PES, yayin da gwajin EXCELLENT ya nuna cewa EES ba ta da ƙasa da SES wajen rage asarar da aka yi a ƙarshen watanni 9 da kuma abubuwan da suka faru na asibiti a watanni 12.38 A ƙarshe, Xience stent ya nuna fa'idodi fiye da BMS a yanayin ST-segment elevation myocardial infarction (MI).39
EPCs wani ɓangare ne na ƙwayoyin da ke zagayawa waɗanda ke da hannu a cikin gyaran jijiyoyin jini da gyaran endothelial. Inganta EPCs a wurin da raunin jijiyoyin jini zai haɓaka sake dawo da endothelialization da wuri, wanda zai iya rage haɗarin yunƙurin farko na ilimin halittar ST.EPC a fannin ƙirar stent shine stent Genous stent mai ɗauke da ƙwayoyin cuta na CD34, wanda ke da ikon ɗaure EPCs ta hanyar alamomin hematopoietic don haɓaka sake dawo da endothelialization. Kodayake binciken farko ya kasance mai ƙarfafa gwiwa, shaidu na baya-bayan nan sun nuna yawan TVR.40
Idan aka yi la'akari da illolin da ka iya haifar da jinkirin warkarwa da polymer ke haifarwa, wanda ke da alaƙa da haɗarin ST, polymers masu bioabsorbable suna ba da fa'idodin DES, suna guje wa damuwa na dogon lokaci game da juriyar polymer. Zuwa yanzu, an amince da tsarin bioabsorbable daban-daban (misali Nobori da Biomatrix, biolimus eluting stent, Synergy, EES, Ultimaster, SES), amma wallafe-wallafen da ke tallafawa sakamakonsu na dogon lokaci suna da iyaka.41
Kayan da za a iya shaƙa su da rai suna da fa'idar nazari na farko ta samar da tallafi na injiniya lokacin da aka yi la'akari da komawar roba da kuma rage haɗarin dogon lokaci da ke tattare da struts na ƙarfe da ake da su. Sabbin fasahohi sun haifar da haɓaka polymers masu tushen lactic acid (poly-l-lactic acid [PLLA]), amma tsarin stent da yawa suna cikin haɓakawa, kodayake ƙayyade daidaito mafi kyau tsakanin fitar da magani da lalata kinetics ya kasance ƙalubale. Gwajin ABSORB ya nuna aminci da ingancin stents na PLLA na everolimus.43 Gyaran stent na ƙarni na biyu na Absorb ya kasance ci gaba fiye da wanda ya gabata tare da kyakkyawan bin diddigin shekaru 2.44 Gwajin ABSORB II da ke gudana, gwajin farko da aka yi bazuwar da aka kwatanta stent na Absorb da stent na Xience Prime, ya kamata ya samar da ƙarin bayanai, kuma sakamakon farko da ake da shi yana da alƙawari.45 Duk da haka, ya kamata a fayyace yanayin da ya dace, dabarun dasawa mafi kyau, da kuma bayanin aminci ga raunukan zuciya.
Thrombosis a cikin BMS da DES yana da mummunan sakamako na asibiti. A cikin rajistar marasa lafiya da aka dasa DES, kashi 47% na waɗanda suka kamu da cutar ST sun mutu, kashi 60% daga MI mara mutuwa, da kuma kashi 7% daga angina mara tabbas. PCI a cikin gaggawa ST yawanci ba shi da kyau, tare da sake dawowa a cikin kashi 12% na waɗanda suka kamu.48
Advanced ST yana da mummunan sakamako na asibiti. A cikin binciken BASKET-LATE, watanni 6 zuwa 18 bayan sanya stent, ƙimar mace-macen zuciya da MI mara mutuwa sun fi yawa a cikin ƙungiyar DES fiye da na ƙungiyar BMS (4.9% da 1.3%, bi da bi).20 Wani bincike na gwaji tara, inda aka bazu ga marasa lafiya 5,261 zuwa SES, PES, ko BMS, ya ba da rahoton cewa a cikin shekaru 4 na bin diddigin, SES (0.6% vs 0%, p=0.025) da PES (0.7%) sun ƙara yawan kamuwa da cutar ST a ƙarshen lokaci idan aka kwatanta da BMS da 0.2%, p=0.028).49 Sabanin haka, a cikin nazarin meta wanda ya haɗa da marasa lafiya 5,108, 21 an ruwaito karuwar 60% na mutuwa ko MI tare da SES idan aka kwatanta da BMS (p=0.03), yayin da PES yana da alaƙa da ƙaruwar 15% mara mahimmanci (Binciken watanni 9 zuwa shekaru 3).
Rijista da yawa, gwaje-gwajen da bazuwar, da kuma nazarin meta-nazari sun binciki haɗarin kamuwa da cutar ST bayan dasa BMS da DES kuma sun ba da rahoton sakamako masu karo da juna. A cikin rajistar marasa lafiya 6,906 da suka karɓi BMS ko DES, babu wani bambanci a cikin sakamakon asibiti ko ƙimar ST a lokacin bin diddigin shekara 1.48 A cikin wani rajista na marasa lafiya 8,146, an gano haɗarin wuce gona da iri na ST mai 0.6%/shekara idan aka kwatanta da BMS.49 Wani nazari na meta na gwaje-gwajen da aka kwatanta SES ko PES tare da BMS ya nuna ƙaruwar haɗarin mace-mace da MI tare da DES na ƙarni na farko idan aka kwatanta da BMS, 21 da wani nazari na meta na marasa lafiya 4,545 da aka ware zuwa SES ko Babu wani bambanci a cikin faruwar ST tsakanin PES da BMS a cikin shekaru 4 na bin diddigin.50 Sauran nazarin gaske sun nuna ƙaruwar haɗarin ci gaba da ST da MI a cikin marasa lafiya da suka karɓi DES na ƙarni na farko bayan dakatar da DAPT.51
Ganin shaidun da suka ci karo da juna, bincike da dama da aka tattara da kuma nazarin meta-analyses tare sun tabbatar da cewa DES da BMS na ƙarni na farko ba su bambanta sosai ba a cikin haɗarin mutuwa ko MI, amma SES da PES suna da ƙaruwar haɗarin ST mai ci gaba idan aka kwatanta da BMS. Don duba shaidun da ake da su, Hukumar Abinci da Magunguna ta Amurka (FDA) ta naɗa wani kwamitin ƙwararru53 wanda ya fitar da sanarwa yana mai amincewa da cewa DES na ƙarni na farko yana da tasiri ga alamun da ke kan lakabin kuma cewa haɗarin ST mai ci gaba ƙarami ne amma ƙarami. Babban ƙaruwa. Sakamakon haka, FDA da ƙungiyar sun ba da shawarar tsawaita lokacin DAPT zuwa shekara 1, kodayake akwai ƙarancin bayanai da za su goyi bayan wannan iƙirari.
Kamar yadda aka ambata a baya, an ƙirƙiri DES na ƙarni na biyu tare da fasalulluka na ƙira na zamani. CoCr-EESs sun yi nazarin asibiti mafi zurfi. A cikin wani bincike na meta da Baber et al.54 suka yi, ciki har da marasa lafiya 17,101, CoCr-EES ya rage tabbatacce/mai yiwuwa ST da MI idan aka kwatanta da PES, SES, da ZES bayan watanni 21. A ƙarshe, Palmerini et al. sun nuna a cikin wani bincike na meta na marasa lafiya 16,775 cewa CoCr-EES yana da ƙarancin ST na farko, na ƙarshe, da na shekaru 2 idan aka kwatanta da sauran DES da aka haɗa.55 Nazarin gaske ya nuna raguwar haɗarin ST tare da CoCr-EES idan aka kwatanta da DES na ƙarni na farko.56
An kwatanta Re-ZES da CoCr-EES a cikin gwaje-gwajen RESOLUTE-AC da TWENTE.33,57 Babu wani bambanci mai mahimmanci a cikin yawan mace-mace, bugun zuciya, ko tabbataccen ST tsakanin stent guda biyu.
A cikin wani bincike na cibiyar sadarwa na marasa lafiya 50,844, ciki har da RCTs 49, 58CoCr-EES yana da alaƙa da ƙarancin faruwar ST fiye da BMS, sakamakon da ba a lura da shi ba a wasu DES; raguwar ba wai kawai a cikin Mahimmanci da wuri ba kuma a cikin kwanaki 30 (rabo mara kyau [OR] 0.21, tazara ta amincewa ta 95% [CI] 0.11-0.42) da kuma a shekara 1 (OR 0.27, 95% CI 0.08-0.74) da shekaru 2 (OR 0.35, 95% CI 0.17–0.69). Idan aka kwatanta da PES, SES, da ZES, CoCr-EES yana da alaƙa da ƙarancin faruwar ST a shekara 1.
Farkon ST yana da alaƙa da abubuwa daban-daban. Tsarin plaque da nauyin thrombus sun bayyana suna yin tasiri ga sakamako bayan PCI; 59 Zurfin shigar strut saboda raguwar necrotic core (NC), tsagewar tsakiya a cikin tsayin stent, rabuwa ta biyu tare da ragowar gefuna, ko raguwar gefuna mai mahimmanci Mafi kyawun stenting, cikakken shigarwa, da faɗaɗawa mara cika60 Tsarin magani tare da magungunan antiplatelet ba ya yin tasiri sosai ga faruwar farkon ST: faruwar m da subacute ST yayin DAPT a cikin gwaji na bazuwar kwatanta BMS da DES. Rate ɗin sun yi kama da juna (<1%).61 Don haka, farkon ST ya bayyana yana da alaƙa da raunukan magani da abubuwan tiyata.
A yau, wani abu da aka fi mayar da hankali a kai shi ne ST a ƙarshen/ƙarshen. Idan abubuwan da suka shafi tsari da fasaha sun bayyana suna taka muhimmiyar rawa wajen haɓaka ST mai tsanani da kuma subacute, hanyar da ke haifar da jinkirin faruwar thrombosis ya zama mafi rikitarwa. An ba da shawarar cewa wasu halaye na marasa lafiya na iya zama abubuwan haɗari ga ST mai ci gaba da kuma ci gaba: ciwon suga mellitus, ACS yayin tiyatar farko, gazawar koda, tsufa, raguwar ɗigon fitarwa, manyan abubuwan da suka faru na zuciya a cikin kwanaki 30 na tiyatar farko. Ga BMS da DES, masu canjin tsari, kamar ƙaramin girman tasoshin jini, bifurcations, cutar polyvascular, calcification, jimillar toshewar jimla, dogayen stents, da alama suna da alaƙa da haɗarin ci gaba da ST.62,63 Rashin isasshen martani ga maganin antiplatelet babban abin haɗari ne ga ci gaba da thrombosis na DES 51. Wannan martanin na iya kasancewa saboda rashin bin umarnin majiyyaci, ƙarancin allurai, hulɗar magunguna, abubuwan da ke shafar amsawar magani, bambancin kwayoyin halitta a matakin mai karɓa (musamman juriyar clopidogrel), da haɓaka sauran hanyoyin kunna platelet. Ana ɗaukar neoatherosclerosis a matsayin muhimmin abu. hanyar da ke haifar da gazawar stent na ƙarshen lokaci, gami da ƙarshen ST64 (sashe na "In-stent neoatherosclerosis"). Endothelium ɗin da ke cike da shi yana raba bangon jijiyoyin jini da stent struts daga kwararar jini kuma yana fitar da abubuwan hana thrombosis da vasodilatory. DES yana fallasa bangon jijiyoyin jini ga magungunan hana yaduwa da dandamalin fitar da magunguna tare da tasirin bambanci akan warkarwa da aiki na endothelial, tare da haɗarin thrombosis na ƙarshen lokaci.65 Nazarin cututtuka ya nuna cewa polymers masu ɗorewa na ƙarni na farko na DES na iya ba da gudummawa ga kumburi na dindindin, ajiyar fibrin na yau da kullun, rashin warkar da endothelial, da kuma haɗarin haɓakar thrombosis.3 Rashin lafiyar DES na ƙarshen lokaci ya bayyana wani tsari ne da ke haifar da ST.Virmani et al66 sun ba da rahoton binciken bayan mutuwar bayan mutuwar bayan ST wanda ke nuna faɗaɗa aneurysm a sashin stent tare da halayen rashin lafiyar gida wanda ya ƙunshi T lymphocytes da eosinophils; Waɗannan binciken na iya nuna tasirin polymers marasa narkewa.67 Rashin daidaituwar stent na iya zama saboda faɗaɗa stent mara kyau ko kuma yana faruwa watanni bayan PCI. Kodayake rashin daidaituwar tsari abu ne mai haɗari ga ST mai tsanani da kuma mai tsanani, mahimmancin rashin daidaituwar stent da aka samu a asibiti na iya dogara ne akan sake fasalin jijiyoyin jini mai ƙarfi ko jinkirin warkarwa da miyagun ƙwayoyi suka haifar, amma mahimmancin sa na asibiti yana da ce-ce-ku-ce.68
Tasirin kariya na DES na ƙarni na biyu na iya haɗawa da saurin endothelialization, da kuma bambance-bambance a cikin ƙarfe da tsari na stent, kauri na strut, halayen polymer, da nau'in maganin hana yaduwa, kashi, da kinetics.
Idan aka kwatanta da CoCr-EES, siraran stent na cobalt-chromium (81 µm), magungunan fluoropolymers masu hana thrombosis, ƙarancin polymer, da kuma yawan magunguna na iya taimakawa wajen rage yawan ST. Nazarin gwaji ya nuna cewa zubar da jini da platelet na stents masu rufi da fluoropolymer sun yi ƙasa sosai fiye da na stents marasa ƙarfe.69 Ko wasu DES na ƙarni na biyu suna da irin wannan halaye ya cancanci ƙarin nazari.
Stents na jijiyoyin zuciya suna inganta nasarar tiyatar tiyatar jijiyoyin zuciya idan aka kwatanta da na gargajiya na percutaneous transluminal coronary angioplasty (PTCA), wanda ke da rikitarwa na injiniya (ƙullewar jijiyoyin jini, yankewa, da sauransu) da kuma yawan restenosis (har zuwa 40%–50% na lokuta). Zuwa ƙarshen shekarun 1990, kusan kashi 70% na PCI an yi su ne da dashen BMS.70
Duk da haka, duk da ci gaba a fasaha, dabaru, da magunguna na likitanci, haɗarin sake kamuwa da cutar bayan dasa BMS kusan kashi 20% ne, tare da fiye da kashi 40% a cikin takamaiman ƙananan ƙungiyoyi.71 Gabaɗaya, binciken asibiti ya nuna cewa sake kamuwa da cutar bayan dasa BMS, kamar wanda aka gani tare da PTCA na al'ada, yana ƙaruwa a cikin watanni 3-6 kuma yana ɓacewa bayan shekara 1.72
DES ta ƙara rage yawan kamuwa da ISR,73 duk da cewa wannan raguwar ya dogara ne da angiography da yanayin asibiti. Rufin polymer akan DES yana fitar da magungunan hana kumburi da hana yaduwa, yana hana samuwar neointima, kuma yana jinkirta tsarin gyaran jijiyoyin jini na tsawon watanni zuwa shekaru.74 An lura da ci gaban neointimal mai ɗorewa yayin bin diddigin dogon lokaci bayan dasa DES, wani abu da aka sani da "kamawa a makare", a cikin nazarin asibiti da histological. 75
Raunin jijiyoyin jini a lokacin PCI yana haifar da tsari mai rikitarwa na kumburi da gyarawa cikin ɗan gajeren lokaci (makonni zuwa watanni), wanda ke haifar da endothelialization da rufewar neointimal. A cewar binciken histopathological, neointimal hyperplasia (BMS da DES) bayan dasa stent galibi ya ƙunshi ƙwayoyin tsoka masu santsi masu yaduwa a cikin matrix na extracellular mai arzikin proteoglycan.70
Saboda haka, hyperplasia na neointimal yana wakiltar tsarin gyara wanda ya ƙunshi abubuwan da ke haifar da coagulation da kumburi da kuma ƙwayoyin da ke haifar da yaduwar ƙwayoyin tsoka mai santsi da kuma samuwar matrix na extracellular. Nan da nan bayan PCI, platelets da fibrin suna taruwa a kan bangon jijiyoyin jini kuma suna tattara leukocytes ta hanyar jerin ƙwayoyin mannewa na tantanin halitta. Leukocytes masu juyawa suna manne wa platelets masu mannewa ta hanyar hulɗar da ke tsakanin leukocyte integrin Mac-1 (CD11b/CD18) da platelet glycoprotein Ibα 53 ko fibrinogen da aka ɗaure zuwa platelet glycoprotein IIb/IIIa.76,77
A cewar bayanai masu tasowa, ƙwayoyin halitta da aka samo daga ƙashi suna da hannu a cikin martanin jijiyoyin jini da hanyoyin gyarawa. Haɗakar EPCs daga ƙashi zuwa jinin gefe yana haɓaka sake farfaɗowar endothelial da kuma sake farfaɗowar jijiyoyin jini bayan haihuwa. Da alama ƙwayoyin halitta masu santsi na tsokar ƙashi (SMPC) suna ƙaura zuwa wurin da raunin jijiyoyin jini ya faru, wanda ke haifar da haɓakar ƙwayoyin halitta.78 A baya, an ɗauki ƙwayoyin halitta masu santsi na CD34 a matsayin adadin EPCs da aka ƙayyade; ƙarin bincike sun nuna cewa antigen na saman CD34 a zahiri yana gane ƙwayoyin halitta marasa bambanci waɗanda ke da ikon bambancewa zuwa EPCs da SMPCs. Canza ƙwayoyin halitta masu CD34 zuwa layin EPC ko SMPC ya dogara da yanayin gida; yanayin ischemic yana haifar da bambancewa zuwa yanayin EPC don haɓaka sake farfaɗowa, yayin da yanayin kumburi ke haifar da bambancewa zuwa yanayin SMPC don haɓaka haɓakar ƙwayoyin halitta.79
Ciwon suga yana ƙara haɗarin kamuwa da cutar ISR da kashi 30%–50% bayan an dasa BMS,80 kuma yawan kamuwa da cutar restenosis a cikin marasa lafiya masu ciwon suga idan aka kwatanta da marasa lafiya marasa ciwon suga suma sun ci gaba a zamanin DES. Hanyoyin da ke ƙarƙashin wannan lura wataƙila suna da alaƙa da abubuwa da yawa, waɗanda suka haɗa da tsarin jiki (misali, bambancin amsawar kumburi) da kuma tsarin jiki (misali, ƙananan tasoshin jini, raunuka masu tsayi, cututtukan da ke yaɗuwa, da sauransu) waɗanda ke ƙara yawan kansu. Hadarin ISR.70
Girman jijiyoyin jini da tsawon raunuka sun shafi yawan ISR, tare da ƙananan raunuka/masu tsayi sun ƙara yawan restenosis idan aka kwatanta da manyan raunuka/masu gajeru.71
Dandalin stent na ƙarni na farko sun nuna kauri stent struts da ƙimar ISR mafi girma idan aka kwatanta da dandamalin stent na ƙarni na biyu waɗanda ke da siraran struts.
Bugu da ƙari, yawan kamuwa da cutar restenosis yana da alaƙa da tsawon stent, tare da tsawon stent fiye da 35 mm kusan ninki biyu fiye da waɗanda suka wuce 20 mm. Diamita na ƙarshe na stent mafi ƙarancin lumen shi ma ya taka muhimmiyar rawa: ƙaramin diamita na ƙarshe mafi ƙarancin lumen ya annabta ƙaruwar haɗarin restenosis.81,82
A al'ada, ana ɗaukar hyperplasia ta intimal bayan dasa BMS a matsayin tsayayye, tare da farkon kololuwa tsakanin watanni 6 zuwa shekara 1, sannan kuma ƙarshen lokacin kwanciyar hankali. An bayar da rahoton farkon kololuwar girma ta intimal, sannan kuma komawa baya tare da faɗaɗa lumen shekaru da yawa bayan dasa stent;71 santsi balaga da canje-canje a cikin matrix na extracellular an ba da shawarar su zama hanyoyin da za su iya haifar da koma baya a ƙarshen neointimal.83 Duk da haka, nazarin da aka yi tare da dogon lokaci na bin diddigin sun nuna amsawar triphasic bayan sanya BMS, tare da restenosis da wuri, komawa baya na tsakiya, da kuma sake dawowar lumen late.84
A zamanin DES, an fara nuna ci gaban neointimal a ƙarshen lokacin bayan dasa SES ko PES a cikin samfuran dabbobi.85 Nazarin IVUS da yawa sun nuna raguwar ci gaban intimal da wuri sannan kuma a makara bayan an dasa SES ko PES, wataƙila saboda ci gaban kumburi da ke ci gaba.86
Duk da "kwanciyar hankali" da aka saba dangantawa da ISR, kusan kashi ɗaya bisa uku na marasa lafiya da ke fama da BMS ISR suna kamuwa da ACS.4
Akwai ƙarin shaida da ke nuna cewa kumburi na yau da kullun da/ko rashin isasshen endothelial yana haifar da ci gaba a cikin neoatherosclerosis a cikin BMS da DES (galibi ƙarni na farko na DES), wanda zai iya zama muhimmiyar hanya ga ci gaba a cikin ISR ko ci gaba a cikin ST. Inoue et al. 87 sun ba da rahoton binciken histological daga samfuran gawawwakin bayan dasa ƙwayoyin zuciya na Palmaz-Schatz, suna nuna cewa kumburi a cikin peri-stent na iya hanzarta sabbin canje-canje na atherosclerotic marasa ƙarfi a cikin stent. Wasu bincike na 10 sun nuna cewa nama mai narkewa a cikin BMS, sama da shekaru 5, ya ƙunshi sabon atherosclerosis, tare da ko ba tare da kumburi a cikin peri-stent ba; Samfura daga shari'o'in ACS suna nuna alamun da ba su da wata illa a cikin jijiyoyin zuciya na asali. Tsarin halittar tubalan da ke da ƙwayoyin cuta masu kumfa da ƙwayoyin cholesterol. Bugu da ƙari, lokacin da aka kwatanta BMS da DES, an lura da babban bambanci a lokacin da aka fara samun sabon atherosclerosis.11,12 Canje-canje na atherosclerotic na farko a cikin shigar kumfa na macrophage ya fara watanni 4 bayan dasa SES, yayin da canje-canje iri ɗaya a cikin raunukan BMS suka faru shekaru 2 bayan haka kuma ya kasance abin da ba a saba gani ba har zuwa shekaru 4. Bugu da ƙari, DES stenting don raunuka marasa ƙarfi kamar fibroatherosclerosis na bakin ciki (TCFA) ko fashewa na ciki yana da ɗan gajeren lokaci kafin ci gaba idan aka kwatanta da BMS. Don haka, neoatherosis ya fi yawa kuma yana faruwa da wuri a cikin ƙarni na farko na DES fiye da na BMS, wataƙila saboda wani nau'in pathogenesis daban.
Har yanzu ba a yi nazarin tasirin DES ko DES na ƙarni na biyu a cikin ci gaba ba; kodayake wasu abubuwan da aka lura da su na DES88 na ƙarni na biyu sun nuna ƙarancin kumburi, yawan kamuwa da cutar neoatherosclerosis yayi kama da na ƙarni na farko, amma har yanzu ana buƙatar ƙarin bincike.